If the rumors are true, General Motors may be in the process of developing a new Buick crossover - with a new two-mode plug-in hybrid engine that should take the alternative fuels fight to its competitors.

GM, Daimler, Chrysler and BMW have been jointly developing the two-mode hybrid for some time now, though the Buick application could be the first to see retail sales. GM had previously planned to debut the drivetrain in a plug-in hybrid version of the Saturn VUE.

But now, with Saturn essentially sold off to Penske Automotive, GM will need a car to stick its latest drivetrain in, which is where the new Buick crossover may come in. While the Buick crossover has yet to be revealed to the public and is still in the early stages of development, it is believed that it will sit on the same platform that the Saturn VUE uses, making it a perfect candidate for adopting the two-mode hybrid drivetrain, according to GM Volt.

With no official word from GM at this point, it's difficult to be anything more than speculative, but the market for a plug-in hybrid luxury crossover could be big enough for GM to be seriously considering a Buick-branded plug-in hybrid based on the Saturn VUE. Buick's near-luxury status might even allow for more attractive pricing than would otherwise be feasible given the high-tech powertrain.

Other speculators are predicting that the upcoming Cadillac SRX crossover may eventually receive a variant of the two-mode hybrid drivetrain, which would put it in similar territory to a possible Buick version. Additionally, GM has already confirmed plans to introduce a two-mode hybrid to the Chevrolet Equinox SUV, and this may also end up getting a plug-in hybrid drivetrain in the future.

While GM is remaining quiet about the future production plans of its two-mode hybrid system for now, its plans are expected to be revealed further down the line as development is completed on the new hybrid system. The as-yet unnamed Buick SUV isn't due for production until 2011, about the same time as the Equinox.