I've used various SCSI models, from NEC 7 disk changers to generic SCSI boxes with who knows what drive inside to portable Panasonic laptop-style ones all with good results. As external SCSI stuff is getting a little harder to find these days, it might just be best to go with the cheapest/easiest to find option and work your way up if it isn't satisfactory.
Any trouble finding one, I'm sure I can dig up a very reasonably priced one to send.
