We know definitely of two companies that sells a removable cartridge drive that
works with A/UX.
Advanced Information Concepts sells a drive called the AIC SlimLine, a 45MB
removable hard-disk cartridge system that has A/UX drivers, and SlimLine II, a
dual cartridge system.
The AIC Slimline uses the popular Syquest mechanism and cartridges with their
own proprietary software. Their optional A/UX compatibility software allows
Macintosh OS and A/UX partitions to coexist on a single cartridge.
MicroNet also makes a vast array of drives and tape backups that can be
partitioned to run under A/UX or Mac OS.
For more information, search under: "Advanced Information Concepts" and
"MicroNet"