Here it is:
http://www.oatleyelectronics.com/kits/k140.html
Contrary to what they have written, it is pulse-width modulated at a high enough frequency (have to look for the frequency in the instruction).
Thanks to the shit Australian dollar this kit will cost you about $10 (minus postage of course!).
I have mine running from 14.4V. The supplied heatsinks are insufficient. I replaced them with a Celeron heatsink and fan for the power transistors. Just bent the transistors into an upright position and mounted the heatsink on its side. Used thermal epoxy for the contact. The fan runs from the mobo.
Looks and runs sweet!
Cheers
Memphis