Oh, I hope I can build this tonight! I have a two-story wall for the TLX replacement of the gatehouse. I'm hoping it will work like this - the drawbridge will be cut around the top, but scored at the bottom edge. I didn't think this would work until I realized the drawbridge door has to be raised up to clear the moat edges! I think the non-TLX system of using a ballast box on the door to let it fall open will still work. I'm going to try to craft a system where a wooden beam piece can be affixed to the inside of the wall, preventing the drawbridge from falling open.
This wall piece took a lot of fiddling to work. It will have the fancy topper that the original had. I might toy with some additional texturing, but it seems quite good already.
There are some things I didn't get around to doing yet. I think I can support transparencies for the chains wired through the walls, and just not have the cranks to work them. They'll just flop down on the inside of the wall when the door is up. I haven't figured out how to hook up the portcullis to the wall. I think I might be able to come up with a scheme where it is dropped down from above, but it will require some guide pieces so it slides into the right place, and the main gate will have to be 4 floors tall (which probably isn't terrible... It IS a castle after all).
I haven't made all sorts of variations of the 2-story walls, but those will come. This was probably one of the harder pieces to do for the exterior walls. Before I can use 2-story walls, I need 2-story posts, so that should be next.