I love the ingenuity of Ikea Hackers and many of them have litter box issues that they have successfully resolved. For example, location and space are frequently issues and in A Hol for Kitty, both of these problems are addressed and like all great hacks, it didn't cost much money. The result is shown in photo here, visit the site for more photos and details.
Some hackers go for the style and if that's your priority too take a look at this one: A Cute Catbox, Finally!For additional inspiration for litter boxes and much more, visit the Ikea Hacker, one of my all time favorite sites. And for a selection of litter boxes at a discount follow the link.