I have an OrangePC 660 that, unfortunately, I have to give up as it doesn't fit in my new computer.
It has 64MB RAM (upgradable to 256) and a 300MHz AMD K6-2 (upgradable to 450MHz.) Fits in a PCI slot. It only has ONE problem with it, the onboard fan was brokent so you'll have to get an external powered fan. I tried it with my friend's and it worked perfectly.
Right now it has thermal paste on it as I was fiddling to get it to work in my 20th Aniversary Macintosh. Unfortunately, the angled PCI slot prevents my Ethernet Card from fitting in the slot as well, it also doesn't have an external power source that I can use (like from HDs and CD-ROMs.) So I smothered it with thermal paste, hoping it would work. It does for a little while, then overheats and crashes. But it worked great with a fan/heatsink. So that's all ya need. And maybe a paper towel to clean off the paste.
I'm looking for between $200 and $250, or best offer. Want to avoid eBay right now. If you're inerested, just post here.