Hi Mark, you know what?
We thought about it because it is actually very scenic.
But in our experience as a player, leveling one on top of the other is a quite a pain in..... while you play. It has always been easier for us to have the levels next to each other so that we can view them as a whole without being able to move things, like when one part of the group remains below and the other above!
In any case, if the most like it, we can easily think of making rigid mini-mat.
For the ideas, we thought about if it is possible to get second level in the dungeon with some stairs and maybe mats of smaller size to put them on top of the others. Not sure if thats possible but wanted to share the idea
I like surprises!!