Firewire is a nice low overhead interface which has many of the advantages of SCSI (not necessarily Apple SCSI, mind you, but SCSI in general) and which easily outruns USB-2. The fact that it can be daisy-chained is always a plus, too.

There's no reason a SCSI-Firewire adapter wouldn't work, BTW - a block device is a block device, after all.