You might as well buy another Raq4 on eBay. No one sells individual motherboards at reasonable prices -- the Raq m'boards were custom and essentially don't exist anymore.
If you want a repair service, I believe that RaqWare (Front Street Networks), RaqTweak, RaqPort, and others offer various repair services, but it sounds like you've been through that already. There's a 4i on eBay that at the moment for $31, though that is likely to go up, whereas the refurb process at RaqWare is $159, plus $75 for a bad ROM, and that is for a board you already own.
I always reccomend http://www.raqware.com/ for bios replacement and I think he only charges $129usd out the door... just as long as the board isn't damaged he should be able to fix it for you.
Actually I'm sending my duds there since I know the boards are good except for the blown bios... and that's better then e-bay in my book! I get a motherboard I know is good working again and I don't have to worry about buying something with bad caps or other problems...