The "Poker standard" for 60% cases is a simple tray. All parts are dumped into it from the top and then bolted in.
TKL cases that would fit Filco/CM QFR/Phantom need to have a top and a bottom. Making the spacing between key-groups fit is much harder than just four edges. The top and bottom have to fit each other, and might need threaded inserts to fit together sturdily that might require some manual work, not just CNC'd wood.
There have been a few custom-made cases in wood, most with both top and bottom and some with floating keys.
Some ideas were flung around for a community project on Deskthority. One was to have solid wood for the sides and floating keys in the middle, inspired by audio mixing equipment. Another thing made for that project w as that Matt3o made a few prototypes out of layers of laser-cut plywood similar to laser-cut acrylic cases ... but then he went away on his own and introduced the WhiteFox with metal case instead.
