Maybe at this point this should be moved Accessories and Mods, but here's another idea I was thinking of.
1) Keep the original gauge circuit board
2) Make the slim backing out of foam, then lay up fiberglass. Cut holes for connector and screw.
3) Replace the front bezel/faceplate with a dremel cut sheet of lexan with standoff posts on the back of the lexan to keep it off the needles etc
5) Mask off the holes for the dials on the back of the lexan faceplate. Sand everywhere on the back of the lexan to make it opaque and promote adhesion. Paint the back of the lexan sheet black. The goal is to get a black glass look (think the back of an iPhone)
6) Peel off masking to reveal the still transparent circles for the dials. The rest looks like "black glass".
7) Mark off where the indicator lights will be on the lexan faceplate based on the circuit board (top between the dials). Get a fiberglass spot sanding pen and remove the paint so those LEDs can shine through the opaque lexan. I still haven't figured out how to get the engine, fuel pump... symbols on there. Thinking maybe of applying them on the front of the lexan faceplate somehow.

Mount the lexan faceplate to the circuit board and dials (I want to make custom dial faces, but I'm not sure how yet). I'm thinking glue with the standoff's to maintain separation between the inside of the lexan and the needs but not sure.
9) Slide the lexan faceplate and circuit board into the slim fiberglass back.
I know a million things could present problems here, but that's the idea. I'm thinking a slim gauge cluster with a completely smooth front surface and no edge (or bezel). The look is kind of glass cockpit, but with analog gauges.
It would use the stock gauges, so save the ECU reflashing trouble. Also, it would be pretty unique.