A plowdozer!
...
Actually...small chassi, large tower with spear gun/flame thrower or claw/guided missiles (they looked the same as heat-seeking in garage and lobby but different in battle, I think
).
I actually really liked the looks of razor discs, alone on a small chassi.
And I used claw + guided missiles to flip everyone over the edge, since it was harder to do than with remote charges
...Man if RR came back I'd do this whole day xD
I can't really say on the wheels, I used 4 large or 3 small, cause 3 small revealed the robot more and you could use more space to show off your painting skills
4 large obviously looked cool, especially with the small chassi, honestly I think 6 small looked kind of hilarious, if you want the worst setup, it would be 6 small wheels on a large chassi with a small tower.