Picked up BetXen's TP9100 last week (thanks!).
Unfortunately, 4 bays had dummy carriers installed, so now I'm looking for four real drive sleds.
This is the 2Gb FC model, so the carrier modules look like this:
Attachment:
1-10.drive_carrier_module.gif [ 14.46 KiB | Viewed 106 times ]
The dummies look like this:
Attachment:
1-12.drive_carrier_dummy.gif [ 5.57 KiB | Viewed 106 times ]
I don't need FC disks; just carriers.
_________________
Now this is a deep dark secret, so everybody keep it quiet 
It turns out that when reset, the WD33C93 defaults to a SCSI ID of 0, and it was simpler to leave it that way... -- Dave Olson, in comp.sys.sgiCurrently in commercial service:

(2x)

In the
museum: almost every MIPS/IRIX system.
Wanted: GM1 board for Professional Series GT graphics (030-0076-003, 030-0076-004)