Ok, so here are the specifics. Doors and outer sides are 3/4 birch plywood. Top and bottom are 3/4" oak plywood (they ran out of birch). Back piece and inner sides are 1 1/8 subfloor plywood. The inner side pieces stop 4 inches from the top. It is used to support the cross braces. For the front cross brace I glued and screwed 4 pieces of 3/4 birch (about 46.5x4" pieces). There are 6 more single cross braces of the same plywood going back spaced at about 3.5 inches. Pretty much all the load is support by 1 1/8 subfloor ply and not by the outer side pieces.