I’ve been building a lot of frankenstein machines lately - the kinds where you patch together pieces from different computers, with varying results. Here’s two I built recently:
t5135 with internal Belkin USB nic
This one didn’t turn out so hot:
PC Chips V21G VIA C7, APEX Case, Morex Power Supply
This one turned out awesome, and didn’t require and damaging modifications.
The power supply is mounted to the back panel, and the power adapter even fit in the top left hand, and I used a few pieces of double sided tape to keep it in place. This system has an onboard nic (VIA Rhine), two intel gigE low profile cards, a VIA C7 processor, 512MB of RAM, and a 32 disk-on-module running m0n0wall. It only uses about 24 watts of power, and we’re currently using it as our production bridge. I’m really happy with this setup, and may build more like it!