• 8 Forgotten Concepts That Should Have Made it to Production

From the "could-have-beens" to the "should-have-beens," these concept vehicles didn’t deserve the exits they received

Concept cars are often the result of an automaker’s desire to showcase possibilities. Very rarely, though, do these possibilities translate to reality. Some concepts get used as springboards for future production models. Some get used as blueprints for future technologies. But more often than not, a lot of concept cars get sent back to the shadows, never to be heard from again. It’s a shame because the concept cars on this list didn’t deserve that fates they received. These concepts should’ve been turned into production models. Unfortunately, for one reason or another, none of them did, and all we’re left with our thoughts of what could’ve been.

Lotus Eterne

2015 Lotus Eterne Exterior Computer Renderings and Photoshop
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This entry could really be any one of the five concept cars that Lotus unveiled in 2013, but the Eterne gets the nod because of what it could have represented for Lotus if it had the money to build it.

The Eterne was supposed to be Lotus’ first hybrid four-door super saloon. It had killer looks that evoked images of Aston Martin, a level that nobody thought Lotus would be able to achieve.

And yet, the Eterne showed that it was possible. Just as important as its looks, the Eterne also had a killer powertrain that’s made up of a 5.0-liter V-8 engine to go along with integrated electric motors and a KERS system. That combination resulted in an output of 620 horsepower and 531 pound-feet of torque. All that power also translated to sick performance times. Lotus claimed that the Eterne would be able to sprint from 0 to 60 mph in four seconds and hit a top speed of 195 mph. No one’s going to remember the concept now, but that’s going to change if Lotus, which is far better shape financially these days, decides to dust off and bring it back to life.

Read our full review on the 2015 Lotus Eterne Concept.

Saab Aero-X

2007 Saab Aero-X
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This concept is unlikely to ever see production because the company that’s behind it has gone belly up. That said, the Saab Aero-X Concept really was something else.

Unveiled in 2006, the Aero-X came at a time when sustainable energy sources occupied a tiny speck of the industry’s consciousness.

But that’s how Saan presented the Aero-X Concept. Beyond its looks — it had a jet-inspired cockpit canopy — the concept was powered by a BioPower V-6 engine that ran entirely on ethanol, a sustainable energy source that’s far gentler to the environment than fossil CO2 emissions. Obviously, the narrative on sustainable energy sources has shifted dramatically to electrification, but that shouldn’t be taken away from the Aero-X. If Saab had the money to produce it, there’s no telling what kind of effect the model would’ve had in the business 12 years ago. We’ll never find out now because Saab is out of business, but it’s still something to think about given where the industry is today compared to where it was in 2006.

Read our full review on the 2007 Saab Aero-X.

Cadillac Ciel

2011 Cadillac Ciel Concept High Resolution Exterior
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If there’s a company that has a habit of teasing us with jaw-dropping concepts that ultimately end up nowhere, it’s Cadillac. From the Elmiraj luxury coupe concept to the Escala four-door concept that may or may not enter production, the American automaker often leaves us with our jaws on the floor when it has a new concept in tow. None of these concepts, though, can compare to what is arguably Cadillac’s masterpiece, the Ciel Concept.

It’s been seven years since the Ciel Concept entered our lives and, to this day, no concept that’s been created since has approached the level of the Ciel.

When it arrived in 2011, the idea was to create a modern interpretation of the iconic touring cars of the past, some of which Cadillac built. Not only did the Ciel cause a stir when it debuted at Pebble Beach — seriously, take a look at it! — it became so famous that it appeared in the Entourage movie. The Ciel wasn’t just looker; it also featured a GM-sourced, 3.6-liter, twin-turbocharged, V-6 that produced 425 horsepower, augmented in part by a hybrid system that also used lithium-ion batteries. Say what you will about the other concept vehicles that should’ve made production, but if the Cadillac Ciel isn’t on that list, then something’s very wrong with it.

Read our full review on the 2011 Cadillac Ciel.

Mercedes-Benz Ener-G-Force

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Admit it. One look at the Mercedes-Benz Ener-G-Force and you knew — you just knew — that it would never become a production model. That’s the tricky game automakers like Mercedes-Benz play with us. They give us something so provocative in design and function that we immediately start clamoring to see a production model even if we know, from years of history and experience, that it would never happen. And yet, here I am, still pining for the day that we see this outrageous concept in production flesh.

Everything about the Ener-G-Force Concept stands out, even if it’s for the wrong reasons.

The large profile of the SUV magnifies its king off-roader personality. Seriously, you’re not going to sweat out the elements when you’re inside this vehicle. It looks tough enough to traverse all manners of road trickery, real or imagined. It even has new age tech like a roof-mounted "Terra-Scan" device that evaluates surrounding surfaces and automatically adjusts the suspension’s spring and damper rates so you can go about your business without even breaking a sweat. It’s hard to imagine that the Ener-G-Force was Mercedes’ vision for the future of the G-Wagen. Considering how the latter’s looks haven’t changed since its inception, don’t expect the Ener-G-Force to come around the corner anytime soon. We’d all love to see it, though, right?

Jaguar C-X75

2010 Jaguar C-X75 High Resolution Exterior
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Speaking of concepts that should never be left off any “it should have made production” lists, the Jaguar C-X75 sits on top of that list with the Cadillac Ciel. The C-X75 actually shouldn’t even be eligible on that list because Jaguar actually planned to put the car up for production a number of times in the past. But for one reason or another, those plans never came to fruition, leaving all of us with C-X75-sized holes in our hearts.

It was disheartening to hear Jag give up on the concept’s production plans. It’s even more heart-breaking when you get a good look at the C-X75 Concept.

If it turned into a production model with its design intact, it could’ve become this generation’s McLaren F1, not so much in terms of its performance, but in terms of its overall package.

It’s true that Jaguar never mentioned the C-X75’s power figures, but the common belief at that time was that it was going to use Jag’s famous V-8 unit, tuned to produce somewhere in the neighborhood of 600 horsepower and 516 pound-feet of torque. The power figures, of course, only paint one part of the whole picture. Anybody who has ever seen the concept will attest that there are only a handful of concepts that have looked as stunning as the Jaguar C-X75 Concept. That’s not even up for debate.

Read our full review on the 2010 Jaguar C-X75.

Lamborghini Estoque

2009 Lamborghini Estoque
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Lamborghini has produced its share of classics over the years, so it is surprising that a concept vehicle it built in 2008 never made it to the production. If it did, we’d probably be talking about it as one of the most famous Lamborghinis of all time. The Lamborghini Estoque should be more relevant than it has been since it made its debut a decade ago. Back then, it was pegged as Lamborghini’s first four-door sedan, a revolutionary model from a company that rarely ventured anywhere outside the supercar world.

Unfortunately, the Estoque never made it to production, becoming one of the biggest “what-ifs” in the Italian automaker’s history.

The Estoque had a different profile than other Lambo models, but it still featured the unmistakable design language of the Raging Bull. It was, as Lambo’s press release of the concept said, “the only car that allows you to share the singular driving pleasure of a Lamborghini with more than one person – possibly even with the whole family. And there is still enough room left over for weekend luggage or several golf bags." The Estoque could’ve been the first Lamborghini to fit that description. Except it never did. The good news, though, is that a decade later, Lamborghini finally has a model that perfectly fits that description: the Urus SUV.

Read our full review on the 2009 Lamborghini Estoque.

Saleen S5S Raptor

2008 Saleen S5S Raptor High Resolution Exterior
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Saleen is back in the news with the new S1 supercar, but a decade ago, it was all set to launch a new supercar that would slot below the almighty S7. The model, called the S5S Raptor, had all the tools to become a performance machine for the ages. It had the heritage of Saleen, which was riding high because of the success of the S7. It also had an unmistakable look that evoked similarities to the Ferrari 458 Italia.

Best of all, the Saleen S5S Raptor was supposed to use a 5.0-liter supercharged V-8 that produced 650 horsepower.

Everything was falling into place for the S5S Raptor until Saleen found itself deep in financial problems. The company ended up laying low instead until news of a new supercar — the S1 — has fans getting excited about what the company has in store for its second supercar act. That could’ve been the S5S Raptor, but as fate would have it, that concept is nothing more than a memory now. It’s a shame, too, because the S5S Raptor was destined for great things.

Read our full review on the 2008 Saleen S5S Raptor.

Maserati Birdcage 75th

2006 Maserati Birdcage
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Back in 2005, Maserati presented the Birdcage 75th as a concept car for the future. It’s already 2018 and the concept still looks like it’s from the future. That’s how far advanced Maserati was in the design of the Birdcage. It’s also the reason why it never made it to production. As striking as the Birdcage was — its style, performance, use, and conception were all dialed up to “extreme” — it really never had a chance to get turned into a production model. Think of it as a version of what we see from all these Vision Gran Turismo Concepts. They’re all way beyond our wildest imaginations.

Things could have turned differently, though, if Maserati did a leap of faith and built the car anyway.

If it did, we’d probably look at the Italian marquee very differently today. The Birdcage was actually a collaborative effort between Maserati, Pininfarina, and Motorola. It was developed to showcase the three pillars of Maserati’s identity: design, sports DNA, and technological innovation. The product certainly speaks for itself. Not only was the Birdcage 75th a can’t-miss concept, but it also featured a 6.0-liter V-12 engine that produced more than 700 horsepower. Imagine, for a second, that the Birdcage came to life 13 years ago looking the way it does and having more than 700 horsepower to play with. It’s a pretty picture, isn’t it?

Read our full review on the 2006 Maserati Birdcage 75th.

Kirby Garlitos
Kirby Garlitos
Automotive Aftermarket Expert - kirby@topspeed.com
Kirby’s first exposure into the world of automobiles happened when he caught Knight Rider on television as a five-year old boy. David Hasselhoff didn’t leave much of an impression on him (that happened later on in Baywatch), but KITT certainly did. To this day, Kirby remains convinced that he will one day own a car with the same ‘spirit’ as the original KITT (not the 2008 monstrosity). He doesn't know when that will be, but until then, he’s committed to expressing his love for KITT, and all cars for that matter, here at TopSpeed.  Read full bio
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