[dfukuba]

That looks very nice and pretty well engineered. My suggestions are that you only use one set of omni wheels. You have to admit that you will be getting in to conflict no matter what you do.
The frame does look pretty sound, but with all that material taken out, are you worried about bending at all? these bots go through some pretty hard hits.
But i am very impressed by your design and i look forward to seeing the end product after the next hectic 6 weeks =)
--Dan