This case mod is something I always wanted to do- Two PC systems in one case.
The ITX system I have had around for a year now but wanted to reduce clutter around my office by intergrating it into my main PC case. When the power supply for the ITX system crapped out now was the time to give it a go.
The main PC is a AMD 5000+ X2 with a 8800GT, it pulls 170 watts at idle, the ITX system pulls 24 watts with the Compaq ATX power supply you see in the pictures. The power supply just exhausts into the case, it doesn't get very warm since it is working at 25% of it's rated spec.
The wall plate is a spare with an attached a short CAT5e cable, it plugs right in as does everything else so the ITX board can be removed if needed with little fuss and bother. The mods to the main case were light so things can be reversed if need be. All I did was cut out the stamped fan grill opening in the case and drilled two holes to mount the wall plate.
After that it was a matter of grinding out the holes for the VGA, Power, USB and Keyboard. The power lead is actually a shortened cable so it plugs right in too. The keyboard port wasn't really needed but sometimes a USB keyboard just won't do and I had the PS/2 lead kicking around. Sound is actually used, I just snaked the audio cable through one of the backplate slots to output through my monitors unused crappy speakers.
Monitor supports dual inputs, if I have to access the ITX machine I just hit a button on the LCD and go in via remote desktop.
I still have to pop in a power button in the front of the case, I was going to drill a small hole where the case badge resides and mount it there.
Total cost? Nothing. All the cables and junk were kicking around my attic. The ITX machine works great for a low power home server / torrent downloader.
Gary
P.S. The PII fan tie wrapped on is just insurance, the VIA CPU runs fairly cool.