I suspect GM's stock price would shoot back up upon such an announcement, and there would be unprecedented anticipation for how Apple's co-founder, the visionary Steve Jobs, might bring the same type of innovation to the American automobile industry that he brought to the computer and communications and music industry.
Would it be enough and in time to save them? That I couldn't tell ya, but it'd be just about the best chance they'd have, I'd venture.
While I'm focused on this point, allow me to link back to my recent article asking why Congress hasn't asked GM about their popular, fully-electric car, the EV1, before trying to give them billions of dollars.
The company introduced the EV1 in California in 1996, before killing it inexplicably three years later and, literally, shredding every last one of the much-sought-after vehicles. Several excellent comments left by readers on that article, also look into the related mystery of Texaco having purchased the patent for the second generation battery for the car. The purchase occurred at nearly the same time as the EV1 was taken off the market. The new battery technology is said to have had a superbly long life on a single charge. The purchase effectively took the battery off the market --- has it been heard from since?
Texaco itself was purchased by Chevron just days after they'd bought the rights to the battery in 2000. At the time of the purchase, as coincidence would have it, Condoleeza Rice was on Chevron's board, and Andy Card was GM's VP of Government Relations, according to Wikipedia, where he served until he was selected as George W. Bush's Chief of Staff. Prior to that, from '93 to '98, Card had been President and CEO of the American Automobile Manufacturers Assoc. (AAMA), representing GM, Ford and Chrysler. All just coincidences, of course.
But back to the main point of this item...If Steve Jobs is disinclined to leave Apple, the company he co-founded, in order to take the reins as CEO of the floundering GM, then I suppose I could revise the headline of this piece to read instead:
How to Save the American Automobile Industry in Three Words:
'The Apple iCar'
UPDATE 12/11/08: Looks like a few others were having the same idea just about the time that I was, and in a bit more detail...