Greenfield does make one that goes behind the bottom bracket, but the one I like is the Stabilizer - it goes at the rear end of the left chainstay. I find this position makes for better stability. Only downside is that disk brakes make it hard to mount the stand, since the disk housing is right where the Stabilizer clamp arm wants to go. Ditto spoke holders on the chainstay, they get in the way.

Review and pic here:

http://www.crazyguyonabike.com/revie...hread_id=38350

Neil