To commemorate its sixtieth anniversary, Holden is showing off a two-door concept car that’s getting rave reviews. The Detroit Free Press was so impressed, it led the story by saying, “Where do they find the time? General Motors Australian unit just revealed yet another eye-catching vehicle from the global family of rear-wheel-drive cars developed in the automaker’s Melbourne engineering center.”

Well, maybe.

But, then again, maybe not.

The sharp-eyed, which includes the observant folks at Motor Authority and Motor Trend, have noted that the new Holden Coupe 60 looks remarkably like a Zeta platform based Pontiac GTO proposal originally floated in drawing form several years ago.

The Holden concept features the same roofline, same side coves and the same wheel placement as the GTO drawings.

It is, in short, the same design.

(more after the jump)

Ultimately, that just might be an OK thing. After all, the original drawings were for a new Pontiac GTO. The Holden concept would be the perfect basis for a new GTO, though the way that General Motors is back-pedaling on engine choices for the Camaro and G8 ute do give some cause for doubt that a GTO could get the go ahead in the United States.

Still, it’s there.

The Zeta platform’s full story probably isn’t known outside GM, but what’s publicly known is that the platform was once cancelled as too expensive, then reinstituted as a modified design, then delegated to Holden in Australia on the theory that it could be developed there less expensively. Ultimately, it was put in production in the United States for the Camaro, but primary production was still left in Australia, where it was the basis of the new Commodore, imported here in modified form as the Pontiac G8.

The entire Zeta platform story seems reminiscent of a scene in the movie “Butch Cassidy and the Sundance Kid,” in which the two bank robbers, fleeing the posse, are trapped on a cliff with no further retreat available, except a long drop straight down into the river below. Outnumbered ten to one, Sundance, nevertheless, wants to fight it out with the posse. Butch, favors jumping. Eventually, Sundance reveals the real reason he doesn’t want to jump: “I can’t swim.”

To which, Butch responds, “Hell, the fall will probably kill you.”

That seems to be GM’s posture with the Zeta platform, too.

Knowing what the company now knows about future fuel economy standards and the costs and means of meeting those standards, Zeta is a platform they wish they’d not put into production and, were they able to do it over, would not do.

But, they have committed too much and gone to far to drop the platform now, or even cut back significantly on the products which they had intended to base on it. After all, though GM may have to have 35 mpg under control by 2020, they’ve still got to sell cars in 2010, 2011, and 2012. Planning for those years appears to have rested substantially on the Zeta platform, and it’s too late to design something new or substitute something else.

It is probably unwise to read too much into the decision to display the Holden Coupe 60. But GM does have a history of displaying concept cars which it intends to produce – the Cadillac CTS being merely the latest example – and Holden has certainly become the primary source for Pontiac’s future products. That said, were the vehicle to come to the States, there’s no guarantee that it would have a GTO badge or a V-8.

Still, it might. GM’s clearly putting a V-8 into the Camaro and GM engineers have predicted a safe and secure future for the Chevy engine because it is shared with the truck lines. The thinking at GM appears to be that the economy standards can be managed with product planning, putting a premium price on the V-8 models to keep their sales low enough that more economical engine choices in lower-priced models can serve as an offset when the averages are calculated. That’s not exactly a strategy for selling cars, but it is at least a strategy that allows V-8s to be part of the product mix, provided that the buyer is willing to pay the extra price.