I'm personally in the market for an external disk unit for one of these but stumbled across this:
http://www.ebay.com/itm/Radio-Shack...tage_Computers_Mainframes&hash=item3ce1f04bc5
http://www.ebay.com/itm/Radio-Shack...tage_Computers_Mainframes&hash=item3ce1f04bc5