Jarkko Moilanen didn't want to carry PC and printer together so he merged them. He can now control his Ultimaker with old Win 7 Exo PC tablet (UltiController), download models, slice them and listen music, and everything is built in as one unit. Ingenious idea! I can see this as new standard for 3d printers. There is enough cheep tablets floating around. He states that slicing is somewhat slow, but I think it can be solved with some optimization on software side.
Full story and more details on: http://communities.ossoil.com/2361/diy-ulticontroller-mounted-wetab-on-ultimaker/