loren to the rescue again.

the problem with using the non drive wheels to power the car is that you'll never make enough power to keep the car going.
However, the crafty people would suggest that wiring up/setting up an alternator to be powered by one of the wheels, and that alternator then charge a battery/bank of batteries would in turn assist with gaining additional range before the charge ran out.
Seems like a valid arguement, but I have yet to see anyone actually pull it off.
Hell, I've never even seen someone work out the math to even see if it is as good of an idea as it sounds.
I know from experience that alternators, while not perfect, can generate a decent amount of voltage without taking a whole lot of horsepower away, especially once it gets started.
I would imagine it would be too complicated to run that kind of system on a production car, but would be interesting to work out/try out on a project car.