Amazon has the Litter Robot LRIII for just $319.89 shipped. This machine uses a “patented sifting process thoroughly cleans the litter bed automatically after each use, and its large capacity is ideal for multiple cats–up to four cats per unit.” Product page. Video after the break.
After seven minutes, a clean cycle starts with the slow rotation of the globe in a counter-clockwise direction. The rotation of the globe sifts and separates clumps from the clean clumping litter and deposits all waste in the large-capacity drawer, which can be lined using any standard kitchen garbage bag.