I am building an Amiga 4000T motherboard and its modules at the moment. Here is the disk module for the A4000T. It is almost fully built, missing two double row pin headers and screws for the external SCSI2 port.
The disk module has the internal 50 pin SCSI port and the external SCSI2 port. It also has the SCSI switches (accessible from backside) and floppy port. It is attached to the Amiga 4000T motherboard on a pin header.