[Gooserider]

A really full size tower will maybe work, or you could go the route that I did and get a big server cube style case. I'm using an AMS CK1100B from Servercase.com. This is a really neat case that IMHO is a much better unit than the YY Cube a few folks here have used for projects. (I wrote up a review on it here a while back, but it seems to never have gotten published for some reason...)

The big advantage it has over the YY Cube for this application is that the mobo side chamber is much wider, with 2 5.25" and one 3.5" bay at the top, and a big space underneath that was intended for the main case air intake for an AC system. Behind that space is lots of room between the front of the mobo tray and the front of the chassis. I cut out the sheet metal behind the front bezel so that it (barely) fit my 2-342 single pass rad (~6" W x 9"H (10.5" w/ tanks)) into the front of the case, and built a split duct setup behind it to house the fans (The bottom half of the duct blows out the bottom of the case through a blowhole, the upper half blows into the case for air circulation)

With the front bezel in place, the only thing about the system that doesn't look stock is the fill point for the Res over on the PSU chamber side.

Gooserider