Using blender instead of the map editor?

[Arop Retim]

My map editor is still not working. So I'm looking for an alternative now.
I know blender can be used to create prefabs. But is it possible to use blender to create a whole map as a giant prefab and let someone else with a working map editor convert it to a map file?
I know, modelling a map would be just one small part. There would be much more work to do (speed limits, AI waypoints, rest places, ...). But blender supports custom properties and maybe there is a way to include all these necessary things in only one blend file.

[MandelSoft]

No. Not only is it completely impractical, but you would exceed polygon and draw call limits pretty quickly.