[JesseK]

I really like most of the ideas behind this configuration. There is only one major modification I would make: Cantilever the middle wheels and remove the bent bracket on the outside altogether.

This bracket looks like it will receive all of the load that the wheels will put onto the frame. Its one major weakness is that it will most likely flex/bend in the direction parallel to the drive wheels when the robot is fully loaded at 150lbs or pushing/resisting another 150lb robot. This can be mitigated by adding angle supports along the outer frame, yet a steel cantilevered axle will handle it just as well without the extra parts.

I'm still mulling over how other pieces would react to the various forces imparted upon them during a match, but nothing jumps out at me at the moment.