@SACC-guy
Yeah modern solutions do need to be found. IDE is straightforward enough for the time being, but SCSI is trickier.
@gertsy
I booted the A3000 with an "Install 3.1" floppy and ran HDToolBox from there. The behaviour was as you describe. It did get the manufacturer name and model more or less right, and also didn't work at all if there was no SATA drive in the adapter so it is definitely working in principle.
The adapter has the following jumpers:
"ID1, 2, 4" - without jumpers at the moment so id 0, I have tried other combinations and it shows up in the expected spot in HDToolBox.
"Delay start" not set
"Write protect" not set
"Parity disable" not set
"SCSI terminator" set
"Terminator on" set
The SATA drive is some oldish Seagate one, don't have the model number at hand but I can look it up. I also tried a Fujitsu and it behaves the same way.
The adapters are indeed somewhat costly, but I got mine at a decent price, and since it has worked so well with the CyberStorm SCSI in the A4000, I thought why not

If we get this working, the A3000 will be future-proofed for a long while.
I have a Deneb so I can transfer stuff to and from the A3000. I haven't yet gotten it to boot from the Deneb, though, I'll have to try that a new go at some point. Still, the hard drive would be great so I wouldn't need to necessarily have the Deneb installed all the time. This system is not in such active use, just comes out for shows and meetings every now and then.