Redesigning the WBC to fit Langstroth boxes is not that difficult!
If you already have a Lang' box, build a double (dead air space) hive bottom that is 1 1/4" wider all the way around (22 3/8" x 18 3/4"). Set the Lang' hive in the middle. Glue down two locator blocks 3/4" wide to index each side of the hive body (8 blocks total), 1/2" from the outside edge.
Using 1/2" lap-plank siding, make side pieces for the tapered outer box. These are trapezoids. The top is shorter than the bottom by 1/4", the sides angle in equally. The dead air space between the boxes at the top is 1/2" all the way around, 3/4" at the bottom. Each "lift" (as outer sections are called) are 3/4" taller than the inner box. The taper fit allows them to stack, and the overhang sheds rainwater, keeping the inside warm and dry.
Lay out and cut finger box joints (or dovetails) along the tapers, being sure that the patterns from the long sides fit into fingers on the short sides (one starts with a notch, the other with a finger). The same can be done with 1/2" thick flat wood instead of lap-plank for the outer box.
Make one outer box for each inner box you stack. Make a thin-skirted telescoping cover that fits inside the outer box. Make a fancy roof - it can be matching lap-plank siding, a swoop-up pagoda style roof, or a shiny copper covered lid -- you can go as crazy as you wish, so long as the inner hive box is insulated by the outer! (I've even seen one with a dormer on a hip roof with shingles). A tunnel is built between the inner hive and the outer box so that the bees don't build comb in between the inner and outer boxes.
For that much work, I would opt for a beautiful, durable wood. I would use clear water seal or clear weather-resistant finish. I would make tracing patterns, and use scrap wood for a test-run before buying cocobolo or rosewood. It could be a beautiful accent to your garden, and a source of pride for years to come. The bees love them!