First question ... are you SCSI -I or II
External SCSI CD R/W drives are not that hard to find.
( I just sold one on EBay not long ago)
Anyway, its my understanding that most SCSI
devices are backward compatable.
AFAIK a SCSI II device should be compatable on
a SCSI I controller. For CD Roms it should be easy
but for harddrives the compatability can get
alot more picky.