I made a new bezel out of 3/16 phenolic material for the gauges on my boat when I swapped the speedo for a round radio that required a bit smaller hole. I also used it making new gauge and switch panels for my hot rod.
The phenolic tools with normal wood working tools, and is basically impervious to moisture while not being conductive. It is amazingly strong for its thickness too. It's available in natural (brownish color) and black (more of a carbon fiber look). It is paintable too. You can order it online in just about any thickness you want.
If you're not living on the edge, you're taking up too much space!