It's been suggested before, but I don't think anyone's gone through with it yet, here or elsewhere on the 'tubes. I could be wrong.

You might like to check the Commodore Disk Drive MiniITX mod over at mini-itx.com, and the Mini Centris. NB: the adapter board for drives that he uses is only needed for the PPC Mini - the Intel Minis use SATA connectors.