This was a proof of concept for a Three.js frontend and Twisted Python backend multiplayer 3D RTS game. Made from scratch in around three months, it uses an entity model publishing protocol and has a debug mode.
To run SMOG you need to have python twisted and autobahn installed. You can then execute the 'run' script that starts a server on port 8080. You can then visit that port on localhost:8080/index.html and should see a plane with some cubes.
You should be able to pick and place cubes, delete and spawn them also. This could easily be extended to function as a full RTS game will a little bit of work. I may come back and fork this for that reason.