I updated the viewer in the first message and the file extractor in the fifth message.
The viewer now exports the scene into a collada .dae file if you press 'c' while the scene is visible. It's quick and dirty but gives you the geometry and textures. The Blender collada plugin doesn't seem to handle vertex colours, or my export of vertex colours is wrong, as they come out as all white. And transparency is not exported, yet. The file doesn't work with Sketchup, though you can re-export it from Blender and import that into Sketchup. But then you seem to lose the textures? The file name is level<room>.dae .
You may want to adjust the far clipping plane in Blender to something big to avoid the scene to be cut off. You can enable textured view, but shaded view is all black because there is no light.
I'll need to dive into the source for the collada plugin at some point to see if I can improve that, but for now I'm too busy.
The file extractor now calculates the size of movie files correctly.