Get in touch with a trophy shop and see if they can get matte flexibrass material. It's usually gold/silver/bronze in color and used for trophies and such (hence the usual colors) but the manufacturers of the material (Rowmark & others) do have a lot of material choices (including matte) and they all can easily be laser cut to the shapes you need. Flexibrass has minimal thickness with 3M adhesive backing.
I had done the same thing while in the sign industry, only I used contour cut vehicle wrap vinyl that was printed to match the texture on my camera. A couple of little laser cut pieces of flexi is at most a couple of bucks.
In my opinion, the trophy shop is the much better choice. It may be best for you to do all the design work as most trophy shops do not employ designers that actually know how to take a photo and draw to scale from it.
It looks like you're proficient enough in Photoshop to accomplish this yourself, but let me know if you need any help with any part of it, as I now work with flexibrass and plastic on a daily basis engraving & cutting with a CO2 laser.