Thanks, I've still got to decide what height adaptor to use but I at least know what to look for now. I'd really like to keep the overall package height to about 2 inches so it looks like a part of my av equipment instead of a computer sitting on my shelf.
The case itself I am going to make myself, I have a bench bender out in my shop and a ton of aluminum laying around so I'm going to form my own case to my specifications.
The motherboard is a Biostar M7VIK and I've got an Athlon 2400 sitting around, I figure that will be more than enough for any of my home theatre pc needs. The video card is a Volari V8 video card, not top notch for 3D stuff, but it will output HDTV native resolutions and really looks better on my tv than my Radeon ever does.
I have my Xbox set up with XBMC, but I have these components just laying around, and I've always wanted to build a dedicated home theatre pc.