Look what I just found!

sd0 at scsibus0 target 2 lun 0:  disk fixed
sd0: 41046 KB, 928 cyl, 2 head, 44 sec, 512 bytes/sect x 82092 sectors
sd0: sync (248.00ns offset 8), 8-bit (4.032MB/s) transfers

It's a 3.5" SCSI hard disk and it seems to work, albeit slowly (write 641 K/S, read 836 K/S). It might suit an Atari ST, Amiga or old Apple Mac. Anyone know a collector? :-)