This would be sweet! I think it would be more fun (from a gameplay standpoint) if it was added to an existing map, but for videos (which I assume is why you’d like to use it) it would be better as a standalone map.
Just to save consultation time, could you clarify on the following?: Can the map consist of only the theater grounds, or should there be more map beyond just the background? Are you willing to allow the use of official assets (materials, foliage, etc.)? And, Is this theater supposed to be in-use today, is it abandoned, or in some state of dereliction?