Hi there - thought it was about time I gave an update.
Last year I spotted an external HD (512MB) with ICD interface (the last one they released, with the RTC) enclosed in a really nice scsi case complete with SCSI pass through's and ID selectors on eBay. Amazingly, I managed to get hold of it for £100 (I thought it was going to go for a lot more with the ICD card inside!).
I then purchased HDDriver, a SCSI zip drive and a USB zip drive.
I installed HDDriver on the Atari HD, with a C boot partition and a D data partition. I then formatted my zip disks (attached to the scsi passthrough port) as TOS/WIN. This means that I can now really easily copy 100MB at a time from my PC to my STE.
I still have the 50MB Supradrive (currently unused and underneath my desk).
A couple of nights ago (under GGN's guidance) I purchased an ACard AEC-7720U (Support ATAPI Device) : Ultra SCSI-to-IDE Bridge for £80, and a IDE-to-SD Card interface (for about a tenner). My intention is to remove my super noisy SCSI HD and futureproof my Atari via installing a SD card in its place.
I did think about a UltraSatan, but I wanted a solution that would be reliable and fit inside my external scsi housing (so I could still use my Zips for fast and easy data transfer).
When the kit arrives and I get it set up I will provide some more info.