are u looking for a single drive or multiple drive ?
the only thing ive ever seen that does this was in a server room, was a box with 4 X 160g scsi drives, box has 2 netcards and it runs and embedid version of windows (rom based) on a processor card.
basically 720g hdd space available, if u want more info i can contact my customer and find out who supplied them with box etc etc
just done a search on the net lecie seem to do stuff but i hope u have deep pockets £420 for a 500g drive
You can also get a small device made by a company called the Ximeta Netdisk. It is the size of an external 3.5" drive and can connect via ethernet. Smartdisk have also licenced the technology from Ximeta, so they have their own version of the Netdisk that almost looks identical apart from the name tag.
Do a search for Ximeta Netdisk and / or Smartdisk Netdisk.