IIndieGoGo started out as a Kickstarter-like site for people to get funding for art projects. Then the site evolved to offering prototype projects and one of the latest is the Aimicat, an automatic cleaning litter box.
Besides removing waste as soon as the cat is done, this robotic litter box also includes an air filter to reduce the odor that normally comes from a litter box. Of course the trick is getting your cat to use this litter box but at least your cat will likely want to play in the cardboard box that it comes in.