There is nothing special about the SCSI drives used in the Quadras, they're just ordinary consumer grade narrow SCSI drives.
Do a search on the forum for Seagate Savvio, there has been quite a bit of discussion. I bought a couple some time ago that I run in a couple of my old Macs. I believe Uniserver bought a whole pile of them, usually they can be found for 10-15 bucks plus a few dollars for the adapter board and a few more for a bracket to mount it in the 3.5" space.
If you don't care about noise, lots of 10K U320 server drives will work, but the 3.5" ones tend to scream like a jet taking off.
Do a search on the forum for Seagate Savvio, there has been quite a bit of discussion. I bought a couple some time ago that I run in a couple of my old Macs. I believe Uniserver bought a whole pile of them, usually they can be found for 10-15 bucks plus a few dollars for the adapter board and a few more for a bracket to mount it in the 3.5" space.
If you don't care about noise, lots of 10K U320 server drives will work, but the 3.5" ones tend to scream like a jet taking off.