Team 1625 built a 6WD swerve in 2010. It ended up playing on Einstein.
If you search through Aren Hill's recent posts, he's got some solid information and pictures out there. Or PM directly if he doesn't post in this thread.
I believe that 1625's 6WD swerve is the first and only 6WD Swerve.
Good picture in this post:
http://www.chiefdelphi.com/forums/sh...7&postcount=21