Possible solution for you.
I'm currently using an 18Gb UltraStarXP on my 1200 through 1230scsi.device. Works beautifully. I don't know what type of connection your drive uses, but there's an 80Pin->50Pin adaptor on mine that also overrides the drive's built-in jumpers and power connections, bringing the drive down to a much more Amiga-friendly configuration.
Maybe you could experiment with adaptors or a different SCSI controller?
