I'm working on porting a node/websockets game I wrote to python using the twisted websockets branch. (not integrated in core yet but fully functional so far)

Instead of using socketio I rewrote the client side code in pure js. It was not difficult at all, and nearly all browsers support websockets now anyway.

Anyway - if you've written a twisted server before then writing a websocket backend is trivial, and the frontend is not much more difficult. I might do a full writeup when the project is complete.