This is a link to my post in the "650b and other strange sizes" forum.

http://forums.mtbr.com/showthread.php?t=502570

The other post will explain better, but basically I built up a Motobecane cross frame and fork specifically as a fatter tired 650b all-rounder type bike. I'm having great fun with it on and off road.

I can't really say enough about the quality of the frame- good quality. I was very surprised, given the cost.