Here's a photo of K3, the undocumented and underappreciated replacement for Killercarrot2. The 25mmx3mm box chassis was designed around a 100x125 16bar ram, T type axles, a pair of CIM2 motors balanced at 36v, and Pro 120 speed controllers. The regulator was a very nice Kenmac high flow unit, and all the plumbing was custom built in the Hydraquip workshops at Crawley. The body is armoured at the front by heat treated steel, and the end of the flipper plate is cut from a laminated steel plough body.
The blog of the killercarrot robots, how we built and fought and broke them.