Ugly as sin!!
J/k. Looks good. I have one question though, why did you put a strip of heat tape on the back and not run it on the floor? I've run heat tape on the side of my GTP cage and it warmed it up but didnt give a very good gradient. Also running heat tape between the cages can give you a double benefit in that it provides a warm spot on the upper cage and will kind of heat the air in the lower cage above the lower cages hot spot.
Also a bit of advice, if you ever use the bottom cage for a snake, throw down a sheet of 1/2 inch or 3/4 inch plywood. Cages on the floor tend to get the heat sapped right out of them. At least that is what Bob from Pro Products told me when we were talking.
Otherwise, nice looking set up.
Oh forgot to add, if you cover the heat tape with foil tape, it will help focus the heat more towards the cage and not allow as much to just escape out the other side.