Can you combine it with entities with normal textures, too?
Or, with ventilator's lightmap?

Then, you could achieve this patchwork look of collage/mashup.

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt