Mini-Box.com M300 Mini-ITX Enclosure
 

Not only is the M300 one of the smallest Mini-ITX enclosures with a full height expansion slot, it manages to pack other useful goodies inside as well. Given the size, built in features, and simple good looks, it is easy to recommend for anyone looking for a compact Mini-ITX case with some nice added touches.

http://www.bigbruin.com/2007/m300_1