A few weeks ago I put an Apple 8600/250 out of it's missery and took it's SCSI internals (Apple branded CD-drive, OEM IBM 2 GB harddrive and OEM ZIP drive) out and put them into an Amiga 2000 with GPV SCSI controller. It all worked after a quick use of Faaastprep (GVP's 'equivalent' of HD Toolbox). Oh, and I had to strighten out the SCSI termination as it wasn't done properly :-S.
For the CD-drive to be recognized you'd be needing a CD-ROM filesystem. I had a quick browse at Aminet and took the first that came up and it worked instantly. Although it has some problems with disk-changes. I haven't looked at that as the Amiga tends to re-boot in just a couple of seconds.
If you're going to use an external SCSI unit, you've got to make sure the internal SCSI termination has been removed.
A less sexy but yet working method is getting a long SCSI cable and route one of the connectors out of the Amiga (together with a power-supply connector) and fix an internal SCSI cd-drive to it. I used to use my Amiga 3000 like that for quite a while.
