here is the guy that made another one, the "neuortikart" here is his video:
http://www.youtube.com/watch?v=_MT41vARlFM
If you click his name he has a ton more of videos to show how he built it. It sucks that he uses 4 car batterys.
ESC: called sevcon millipack controllers. Here is the link:
http://www.sevcon.com/pages/millipak4Q.html I dont know of the prices.