I will have to take a look at that box - I am working on a similar project but your's is a different approach.
FWIW My present plan is this (to make a "vcr-like" box for my PVR:
Tear apart a standard 300W ATX power supply - cut down the heat sinks and re-attach to a low-profile, wider sink.
use 7v fans and/or thermally controlled fans to make the unit QUIET enough to sit in my living room.
Create my own case from plexiglass - with a Dremmel and some patience, I should be able to make a steel cover from a regular case slide right onto an super low-profile plexiglass chassis. I am shooting for 3 inches - not exactly paper-thin, but certainly more reasonable than a desktop. Here's a nice link about plexi bending:
The last big hurdle is to get the expansion cards flipped on their side. I think the most I can hope for is 3 or 4 cards at best. I am anticipating 1 or 2. With my Hauppauge PC Theater card this means I should go for a fairly loaded motherboard.
OH, last thing - a can of slate-colored, flat enamel (or maybe even appliance enamel) paint. With careful masking you can get very nice results - go look at one of those blue PC's Kodak is putting in retail stores everywhere for digital photo processing. If you pay close attention, you will notice that everything was torn down and painted blue.
The plexi might not be paint-friendly for long-term use. sandblasting to rough the finish will prevent this, but I plan on trying to paint the smooth surface - hoping that whatever is used to carry the paint will melt the plastic a little. I could test this first, but being a habitual GM car owner, I have learned to appreciate peeling enamel paint.
Now, If I could only get my Mailstation 350 LCD and Keyboard into this project I might have a very interesting box, although a 900mHz wireless VT100 would also do the trick...