I know that GGS-Data (
www.ggsdata.se) in Sweden have them. They have tested the bridge/converter with Amiga hardware and they report that it works great. The issue is speed, though. Compared to a real SCSI-harddrive connected to an UW SCSI-controller, the IDE has no chance in speed. But in your case I would dare to say that you would benefit from getting your IDE units into your SCSI-chain! It costs around 60US dollar, and you need one converter for each device.
You can send him an e-mail to get more info:
gunne@ggsdata.se
Have a nice day! =)