So the left one is connected to the SCSI card, while the right one is currently not connected to anything. I spent quite some time thinking about the drive bay. I wanted to have quick access to the drives, so I did not want to use the conventional screw-on technique. What I was looking for was a completely tool-less operation. I ended up going with this.
Lets first look at the outside of the drive bay door.
This piece of wood is held to the front panel by 3 cabinet hinges. The three holes enables the securing of the drives. The picture on the right shows the drive bay opening up. Both drive bays opened up, viewed from the rear of the drawer. The picture on the right is a close-up of the drive supports on one of the bay doors.