If you really want, specifically, an A500 sidecar for IDE devices (and not something newer like an ACA500 or Vampire, or one of the Kipper boards from a couple years ago), try posting a "wanted" ad on a forum such as Amibay. I would check somewhere like the Amiga Hardware Database website or BBOAH and look for the specific item that meets your needs, and ask for it there. Chances are someone may still have one collecting dust somewhere. Good luck!
