OK: I may as well do this now and beat Aaron to it:

Lightweight
ttp://http://www.geocities.com/alex_j_holt/BALDUR3.jpgwww.geocities.com/alex_j_holt/BALDUR3.jpg
Just a Little Baldur
A little invertible box with a scoop at the front designed to survive everything. The scoop works both ways up. The weapon pivots on the side also prevent it gettign stuck on its side
Speciality: Armour

Middleweighthttp://www.geocities.com/alex_j_holt/sith.jpghttp://www.geocities.com/alex_j_holt/sith.jpg
Sith
A basic wedge flipper, the flipper self rights itself and is high pressure pnuematic. The bits at the front are retractable and are pushed out with actuators to get under other robots more effectivly.
Speciality: Jack of all trades.

Heavyweighthttp://www.geocities.com/alex_j_holt/BPQhttp://www.geocities.com/alex_j_holt/BPQ
Black Panther Queen
A pyramid with the tip cut off low down, skirts, and a double headed pnuematic axe and flipper. The flipper is in two halves but attached at the back, so that it doesnt interfere with the axe.
Speciality: Weapons

Superhevyweighthttp://www.geocities.com/alex_j_holt/redknight.jpghttp://www.geocities.com/alex_j_holt/redknight.jpg
Red Knight
OK - the complex one. The main body is quite titchy, its all about the weapon. The weapon pivots off the centre, and follows an opponents direction using motion sensors - and is essentially a huge hardox plate on castors with a 10kg flywheel set into it for damage. Anyway, it basically means that whenever someoen attacks unless they are very fast theyll hit the plate, and the disc.
Speciality: Jack of all trades.