Check this out and see if I'm following you correctly.
This is a link for an AC electric motor. It's 3phase and rated at 10hp and 3600rpms. That seems awfully low for a vehicle. Obviously I'm not looking at the right item but am I on the right track?
01036EP3E215T - WEG ELECTRIC CORP MOTOR 3PH 10HP 3600RPM 215 T 208-230/460V
Here is another motor rated at 20hp @ 1800rpms. It costs $1000 but that is VERY cheap compared to others I've seen. It seems with this type of low rpm motor I'd NEED a transmission to compensate for that. Sure I wouldn't need 6 gears but maybe 3.
http://www.galco.com/scripts/cgiip.e...pnum=U652-MARA