I always thought of a small diesel generator and 4 hub motors, lots of torque ...(electric motors have 100% of torque available at 0 rpm )
This could be done in a GP, generator where the trunk is and all the electronics and relays and controllers to feed the 4 motors in the hood area, manual steering, and heat off the generator, drive the Ac off the generator as well.... I could see 60 - 100 MPG with the setup done correctly.....But I don't have the $$ to do what I've wanted to do since sophomore year of high school(I have my drawings out of those notebooks with a little less detail than I have now )