After turning off Synchronous transfer mode, it's working great now with a initio Miles U2W SCSI card. It did the freezing like on the Jackhammer card, but that was with Synchronous transfer mode on. It seems to work just fine in asynchronous mode. My SCSI Hammer card doesn't seem to be able to toggle sync, so it would alway freeze up when trying to read/write to the drive. This Miles card appears to work perfectly.

I'm now booted off a 15k RPM whisper quiet Ultra 3 HDD.

On top of that, I managed to find a compatible power adapter for my GDock, so now I have serial ports, parallel ports, additional USB ports, and a zip 250 drive.