If I had to guess, I think the EV mod market is too varied to support this type of kit. Too many differences in space available, the desired suspension, power intended, voltage range, track width, range requirements, wheel bolt spacing and finally, a price that competes with wrecking yard prices.

The wrecking yards are going to be very full of motors and full rear ends in the near and long term. Used batteries will have a huge range of uses from EV mods, to solar, to house backup. Motors, controllers, inverters and suspension re-use is a tiny market, so prices will fall from what we see now. The complete Tesla rear end you see today is going to cost far less in a few years. Most totalled Teslas still have a decent rear end in them.

Others can speak to the Volt etc.

It’s a good idea, …but unlikely to be economic.

If you do this math, it helps:

Take the original curb weight of the car, subtract the weight of the engine, the radiator, the gas tank and misc., add a motor at about 125lbs and then 6-800 pounds of batteries. Now look at your frame, suspension, steering and brakes. Now find the space / volume in the vehicle for the batteries. (See a Tesla module and find space for 6-8 of them )

The answer for me was a pickup. The pack is below the cab and between the frame rails. My total weight went down, the brakes and steering could handle it and I have full use of the cab space and bed.

Best of luck!