You could make a few custom destructibles using the hidden terrain models from the game and have them be so and so height above the ground...
And then theres jumping, add/rem edit of metamorphosis ability whereas morphed unit is a flying unit...
Use trigger to change flying height....
Then theres pathing...
Would need to record what level the unit is on...
Have custom pathing textures, and change pathing based on level...
Above levels would have to be removed and added as moving inbetween...
Yeah its very possible, at least I believe it is. Would take alot of work just to have more space.
Better to just make different areas different levels.