I found a guide to using card readers in Akai MPC series samplers:

MPC card reader FAQ

It discusses both ATA/IDE/ATAPI and SCSI readers, but the information there could be useful. For example:

Not compatible:Argus, Spyrus or Litronic. These are for security cards and are not compatible {darn it :-/ }

/

Compatible:

SCSI Intermart PCD series readers: PCD-15, PCD-17, PCD-19, PCD-25.

Microtech PCD-47 with the MPC2000XL and S5000.

Microtech PCD-40, external model, MPC2000(XL) and possibly MPC3000.

Click to expand...

{ATA devices removed}
From experience, if a SCSI drive works with one of these samplers, it is highly likely to work with a Mac. The reverse is not always true.