I just built a test frame for my CPR Space Shuttle glass. If it turns out nice, I'm going to make one for Bally Fathom.
The outer frame is 2.5" oak baseboard and the inner board is just a 1" wide x .5" thick strip of pine. I glued the pieces together in 1 long 8ft strip and used a miter saw for the 45s. Then I used band clamps to glue it in black and L brackets to secure it in the back corners. Once the backglass is fit into place, the backing will be black foam core.
I am obsessing over the finish. I wanted it dark black but keeping the natural oak look without paint filling in the wood grain. I had no idea how hard this is to do with red oak. It have stripped it 3x trying to get this finish right! I will try to take some pictures when I have it complete.