To comment on the swampthing design:
our 2005 design had inset front and rear wheels, which was pointed out earlier, only because of the hexagonal frame shape. I do not believe it improved manuverability, just helps you get out of pin holds (and it does). However the center wheel was lowered about 3/8-1/2", which is quite a bit more than most teams do it. This was an outcome of excess frame warpage during welding, but turned out to be the perfect amount. Reason is those center wheels sink into the pile of the carpet and let the outer wheels drag if you don't lower them enough. But that 2005 chassis had a very well balanced cg in the center of the bot.
I also wanted to bring up our 2007 chassis, which is very interesting and I haven't seen anyone else try it. It actually has the same performance as our 05 chassis, but much easier to design, build and maintain. basically
only the rear 4 wheels are driven, and an extra set is added in the front to give the 6w stability. The thing is keeping the cg over the center wheels. This performs exactly the same as a 6wd but is lighter, simpler and more durable. The misconception I think is more traction is had by driving all 6.
I think we showed the performance of this drive system in the final matches of the championship to everyone that it was more than capable of pushing bots and getting around. Where the majority of your CG is, is where your traction is, so keep it to the center on a 6wd. Also I'll admit, we never once tightened or messed with the chain the whole season. Not 1 single drive train maintenance issue, unlike all of our previous years. Special thanks also goes to the amazing Andymark transmissions.
With 6wd bots you need to have a rigid chassis to keep the teeter action. Also I don't know about other regionals but at nationals, the floor planks are all warped so at times all 6 wheels may touch down. So the more your vertical wheels are offset, the less impact this has. Of course too much wheel offset is a bad thing also, I wouldn't go over a 1/2".