I was actually thinking it would be cool to cut a head tube off and have the frame coming out of the wall, then a cut off steer tube with headset and the stem mounted to that, but that might be too busy and is a bit more work. My plan for my next one is to just take a 4x4 piece of pallet hardwood and cut is into a cube. Drill out a hole in the center and then screw it onto a piece of wood that is... say 1" thick x 10" long by 4" wide (i.e. screw into the cub from the back and then put a large screw on top and bottom into a wall stud. you can sand it and stain and make it took nice and then just stick your stem in that. I used a modolo death stem on my first version, since it cannot see service again.