Hi donnie,
Some ideas which seem good at first glance turn out, well let's say, not so good when actually trying to implement them. Such as an axle motor 6" dia x 4' long. While theoretically possible, it is impractical to make such a motor for a number of reasons which we don't need to get into here. Suffice it to say that such a motor does not exist and to design and make one would cost you more than the price of a new Chevy Volt.
Remember that you need a differential on the rear axle. Take a look for some info on the Ford RangerEV they made back in the late 90s. It used a motor on the rear axle about 12" dia and maybe 18" long. The motor had a gear reducer and differential at one end, shaft to one wheel coming off there and then the shaft going to the other wheel actually went thru the middle of the motor.
You can also use 2 motors (and gear reducers) in place of the rear axle eliminating the mechanical differential and have each motor drive a single wheel.
But if you want to look for long skinny motors, search for submersible pump motors. These are made to slip down inside well casings. But these are not going to be suitable for an EV
major