You could just use RC parts from hobbyking.com.

you'd need 3 things:

1) brushless motor http://www.hobbyking.com/hobbyking/s...00kv_17g_.html
2) brushless speed control http://www.hobbyking.com/hobbyking/s...EC_2_3S_V.html
3) servo tester (to adjust speed without hooking it up to a RC radio) http://www.hobbyking.com/hobbyking/s...vo_Tester.html

Shouldn't cost you more than $25 for all of this