The latest rumor, according to Automotive News, the industry news journal, is that GM is contemplating a smaller Buick, one that would slot in below the current LaCrosse in size and price.

The idea is that Buick would produce a version of the Buick Excelle built and sold in China. The next generation of that car will be a rear wheel drive vehicle built on the corporate Alpha platform.

This is, however, far from a done deal.

(more after the jump)

For one thing, General Motors has earlier suggested that it would favor front wheel drive, particularly for smaller cars, over rear wheel drive because fwd is more fuel efficient and the company needs its mpgs to achieve its CAFE standards under the new law. Second, it is also reported that a school of thought within GM sees a smaller, cheaper Buick as both diminishing the status of the brand and cannibalizing sales from other GM lines. There is also some concern that the Alpha platform may prove too expensive to produce profitably in the United States.

That GM would even consider a car below the LaCrosse just illustrates that the reflex to propagate brands by duplication is far from dead at General Motors. Buick, we have been repeatedly told, is to be a luxury brand at General Motors. Yet, the apparent desire to produce a model that would be a direct competitor to both Chevrolet and Saturn is apparently one that some at GM find themselves unable to resist.

It has been earlier reported that Buick dealers claim their customers are demanding a car smaller than the LaCrosse. These are, presumably, the same dealers who, a few years back, told the company that their buyers preferred large front wheel drive sedans to rear wheel drive, and have been caterwauling for the last couple of years about the absence of a rwd platform from the Buick line-up.

It seems likely that anything and everything is currently open to consideration at GM, as it tries to figure out how it will be meeting the various CAFE standards as they become effective. This much, however, is certain: the locus of Buick’s design and engineering has shifted to China and it would be logical for Buick to seek to capitalize on the work done for the Chinese market to develop a version of the car to sell in the United States.

Whether it is logical from the perspective of GM’s brand structure, however, is another matter.

It will be easier to determine whether a model slotted below the LaCrosse is rational after the new LaCrosse debuts. In conversations with GM executives at the Chicago auto show, there was considerable excitement about the next generation LaCrosse – suggesting that it will be a more stylish and better crafted vehicle than the current model. But, precisely where the new version will figure into the market is not clear, at least not yet. If it goes upmarket, in anticipation of a new rwd large car replacement for the Lucerne, that may give a strong hint that Buick has in mind a third vehicle for the bottom of the line-up.