Hello.
Does anyone know if a bridge board that plugs at the back of a plain old SCSI hard drive exists, to run it connected to an IDE port at the mainboard ? (No ultra, no wide)
Most searches I found show unclear or reversed application.

 

I don't think such a device exists. SCSI is a peer to peer interface, while IDE requires a drive controller. I would think it impossible or very costly to create such an interface, especially since there are factors like unmatching speeds, incompatible commands for talking to the drives. Your best bet is to go with SCSI to USB, or just get a SCSI card.