I have been thinking about getting an old IPC or IPX and swapping out the internals with a modern PC motherboard and components, but only if I can do it cleanly. I haven't done it due to not having enough free time and... it just feels wrong to me in some way.
Ah the trouble of finding a unix workstation with a pristine case and thoroughly cooked interior so you don't feel bad about gutting it for a casemod. Call me when you find one.