Where can I buy a 3kw-4kw hub motor?

http://electricmotorsport.com/store/ems_ev_parts_motors_evthub.php

Also, Mountain Chen (a member of this site) may be willing to sell you a motor.

There is also the Commuter 3500 Motor Controller Kit.

http://www.novascooters.com/product.sc?productId=10&categoryId=10

Philip

I saw this mentioned elsewhere.. Kelly Controllers has expanded their product lineup and now has a line of motors available for astonishing prices.

http://www.kellycontroller.com/

Wow, a 72V 6KW hub motor for $500. Forget fooling around with RC motors to make your old scooter into an electric hotrod. Two of my suppliers told me last year this was coming. In the next few years, the availability of quality affordable EV products here in the US will go through the roof. You can thank the oil industry for all of this. Shows to me necessity still is the mother of invention.