[EStokely]

Rick Tyler said
"I'd build what we did last year: use the kitbot chassis, mount the transmissions and motors near the center, and drive two of the 8-inch Skyway wheels that came in the kit with short chains. Put two hardware store casters (non-swiveling) on the front. Put two more non-swiveling casters on the rear. Set the casters so that either the front or rear just barely touches the floor. You want the weight off one of the sets of casters just enough to make it barely touch. You will be fast, maneuverabl and reliable. You won't win pushing matches, and won't be able to get up on the ramp. It's a straight-forward design that will serve you well, and won't break.
"

I saw it in competition. (I'd say we competed against it but that wouldn't be accurate :-) ) It ran very well. On a flat carpeted field you have many advantages to this type of design.
You Won't be able to get up the ramp though, But if you can stop the other side for getting just one robot up you will "pay" for that loss by preventing the score against you.

Get something running ASAP and practice practice well you get teh idea.
A below average robot with a practiced driver is worth much more than teh right robot with a nervous, untrained driver.