I just finished uploading a bunch of new faceplate designs for the Chameleon enclosure system. You can buy the body, base and blank faceplate for the rest of the enclosure system at Sparkfun. There are numerous metal faceplates you can already buy, but I have often had requests for something with a DB-9 on it, so I created a variety of DB9 plates and even a perforated, ventilated plate.
These can be laser cut most cleanly. I’ve used 1/8” acrylic for custom faceplate designs and that thickness seems to work well and is just thick enough to be fairly strong, but not so thick it becomes difficult to get connectors to protrude correctly.
The license on these designs is Creative Commons, so these are up there as a starting point for your own faceplate designs. Have fun.