I had someone Email me about mounting a PAS-3 in a custom wooden cabinet with just the front face of the PAS-3 showing. Dynaco actually had a "PM-3 panel mount kit" that they sold for doing just this. It had an oversized face plate, two brackets and some associated hardware. The oversized face plate is now "unobtanium" but I have seen PAS-3's mounted in cabinets with the original PAS-3 faceplate. The only caveat I can see here if you do something like this, is to provide adequate ventilation for your PAS-3. As a side note Dynaco also had a "PM-4" panel mount kit for the FM-3 tuner. See below for the spec sheet and instructions on the PM-3 panel mount kit.
Bob
Bob