Assuming the hd isnt dead, you could attempt a hotswap like shown here:http://www.youtube.com/watch?v=4FEgSjw7Rxs
I've done hotswaps in the past, and trust me you will have to keep trying this until you get the timing perfect and the drive detects correctly. The key is to get the ide cables swapped over VERY quickly. Its very much trial and error. Have a search on google for "error 16 hotswap" and read up on it. I believe this is your only option other than a modchip.
You can get the files to rebuild as retail off the Slayer Auto-installer cd, from the usual places. Don't ask me where
Oh, and if dont forget, this is live electronics your messing with here so BE CAREFUL and only attempt this if you know what you are doing!!!