Sometimes you really want to make elements in your backdrop seem huge. At the end of the day, we all have limits to the height we can go to in most venues.
One thing that can help create the illusion of great height is to illustrate the main elements of you backdrop in forced perspective. What this means in the clearest terms is to illustrate in a way that creates an optical illusion that an object is nearer or farther away, larger or smaller than it actually is. This may be most effective with a building, mountain etc. This creates a feeling of great space or confined quarters to help pull off the feeling you’re looking for with your stage.
I’d be happy to talk to you about how forced perspective can help you.