I use an Orb external cartridge SCSI drive on my A2000 and A3000 (I have 1 cart for each divided into 2 x 1GB partitions). It also came with a SCSI-to-USB adapter to use with a PC. When I get home I'll see if I can still find it and test it on the A4000 via the Deneb card. Hopefully the USB stack will treat it as a mass storage device (fingers crossed).
