After experimenting with an EZ-GO 36V golf cart, an Elec-Trak E-14, and a couple of electric scooters, we decided to go for a real conversion.
We stared with a Kawasaki 110 4-wheeler that we bought well used, and rode for 2 years until the transmission let go. It is not the best looking thing, but mechanically it was pretty good (tires, brakes and suspension).
We test fit the Elec-Trak 12 HP 36V motor before we spent any money.
I ordered a Kelly controls 200Amp 36-48V controller, and "hid" it under the tank. I used John's idea from his 750 conversion blog.
This controller comes with a reversing curcuit that doesn't require an additional contactor.
Next we monuted the motor.