3D printer which will print its own body (I hope)
Print onto ABP with stepper as the Z axis, and canter the Y axis at 45deg which may allow very long prints. (STL's will have to be rotated to 45deg in skeinforge)
A bot that can print bigger than itself.
Update 25 Sept 2011, Bot final dimensions 420mm Long x 210mm High x 198mm wide - Print Size 50mm High 215mm Wide.... errr and very long (hopefully)