if anyone wants to make stages, you basically lay down a scene in 3d studio max, then my export plugin will export it in the proper format. It has support for reusing models and textures. The models are stored in a compact binary format and an XML file is used to keep track of positions, rotations, textures, etc. Have to ask shizno about the scale, but I think the characters are like 120 units wide, could be way off.
The exporter uses the underscore character, "_" , to know when objects are duplicated in the scene. So if you want say, multiple copies of the same rock, you make Rock_01, Rock, Rock_2345 and only Rock.bin will be exported and all the <object> instances in the XML file will point at Rock.bin .
Bump mapping should be supported in the future if there's a stage that looks much better with it on. Animation is another posibility, constant rotations or objects that travel around a spline path are do-able.
I would try to keep the total texture usage under 10 megs (uncompressed, no penalty for reusing textures from another object) .
Polycount can be fairly high, but I'm not sure if you even need to make two sided areas since the camera does not change rotation yet.