yeah, ive seen them, scanavo http://www.scanavo.com/ actually makes some real nice multi disc cases. I like the 'overlap' design. they dont seem to sell through their site though.. but you can find some of thier cases on various sites (froogle search scanavo 4 disc overlap, or something like that for where to buy)

you can actually get 6 disc cases that are the size of a standard case (well at least they appear to be in the picture and description, i havent gotten any of them) someone here a while back ordered some of the 4 disc ones in the design im talking about and said they were only slightly bigger than a regular case.

-Darth Simon