For my opinion the present trend of electric vehicles is going a conservative mechanical way. With wheel hub motors the mechanic would disappear i.e. no diff no gearbox no drive shafts only 4 motors with a reasonable KW rating. The un-sprung weight of the wheel is a negative factor but copying something like the Siemens aircraft motor ( 50Kg with 250KW) should do the trick. OK the KW are to high unless you aiming for a Bugatti Veyron type of vehicle. But thinking out of the box no brake disks at the front wheel only emergency handbrake at rear wheels and fully electronic traction control should be possible I do this things with servo motors on industrial roboter’s. Take the wheel motor with only a position sensor as a wearing part if bounced too hard, tire exchange 5 minutes motor exchange 15 minutes. Unfortunately the auto mechanic is a job is reduced to servicing wheel attachment and steering mechanism.
You might want to review this.
http://www.diyelectriccar.com/forums/showthread.php/15-car-hub-motor-799-52336.html
Rodney