bigger sepex?

Have a look at this guy - he may get more stuff on with time

http://www.hitorqueelectric.com/

same guy talking about using forklift motor

http://www.diyelectriccar.com/forums/showthread.php/using-forklift-motor-and-choosing-good-7598.html

while I was looking, I found this comparision of motors

http://www.zev.dk/misc/torque-curves.gif