I've started thinking about this subject lately too, especially after seeing MD2000's set-up. I recently aquired an x-360 e-scooter and the rear end looks about right to go under my metro. Probably need a motor upgrade since it is only 350w
. I would intend on using it for ICE-off low speed (<40mph) cruising and use the ICE for accelerating and hwy use. Seems like the ICE is in a pretty efficient mode under 75% throttle accel anyway and not so much at light throttle cruising. I'd like to talk my boss into letting me try one of the brushless E-tek motors and drives for this
.
Batteries will be a problem though. Don't want too add much mass to the little car.