If you went vertical as Osso suggested you could fit some pretty unique pieces of hardwood, Mr B's specialty, right, Boomer? Maybe that'd bring him on board.
It could even open like a medicine cabinet and it would be perfect for that. What's the total depth of the case?
The hinges are already there, just a nice pinned hardwood latch, bubinga/cocobola, mesquite or even some Pacific NW woods, alder, cedar, redwood, ... SPECTACULAR!!! hand carved by Boomer and Mo, even more spectacular!!!!