I'd think if you wanted to do motors in the wheel, the axle would become the rotor. The motor bearings and axle bearings would then be one and the same. Then you'd have the stator that goes around that, and have to find a way to wrap steering knuckles and rear hubs around that. I'm guessing the easiest solution would be to have a standardized outside dimension for the stator, with a locating tab of some sort, and then just have composite uprights that clamp onto the stator. If you hit things, you'd still be replacing composite parts and bearings, so durability shouldn't be too much of an issue. It's a fascinating idea. I really don't know how you'd replace the power of one of our current TC motors with even 4 smaller ones, and still have them fit inside a steering knuckle, though.
-Mike