I just made a tool allowing to directly unwrap a box representing a stage (one floor and three walls).
The boxmap included texture and included unwrapping in TD are not usable because of non scaled dimensions and non coherent folding. I made an unwrapping tool with a texture continuity between the three walls and between floor and central wall, covering most of the needs for 3D mapping in Theater.
You can choose your texture resolution (but always a square one), your output resolution and you have three cameras outputing three point of view with useful settings : throw, position, rotation and shift.
You can download the .tox, a .toe with example and a .pdf with some explanations.
Feel free to comment, signal bugs and propose features.
Next one will be an uv unwrapper for a convex box.