[a8ksh4]

Would it be important to use a u-joint or some other flexible coupler between the trans output shaft and motor?

I don't think the motor could be mounted up in such a way that it would always be perfectly in-line with the trans... even frame flex from speed-bumps would change alignment since there isn't a big mounting surface between the trans and motor like there is between the trans bell-housing and engine.

Edit:
Oh yah, something would have to be done about powering the brake booster, too, when running off of electric. That might mean using a separate vacuum pump.