Potential solutions for my reverse proxy problem

Apache Websocket module:

https://github.com/disconnect/apache-websocket/blob/master/README.md

Only seems to be able to redirect the websocket to a local binary module, not a backend server via network. Well, I could program my own module to do that, but then I could just write the whole proxy server from scratch.

Make my own

When I would write my own proxy server, I could design it completely to fit my needs. I could add some custom features, like ip-banning people from within the game or adding fake latency and jitter for testing lag compensation.

Using nginx as reverse proxy with this mod:

http://www.letseehere.com/reverse-proxy-web-sockets

Nginx was engineered purely as a reverse proxy, so it would very likely be more efficient than Apache anyway.

HAProxy

https://jfarcand.wordpress.com/2011/10/06/configuring-haproxy-for-websocket/
http://stackoverflow.com/a/4737648

HAProxy is another dedicated reverse proxy application. And as far as I can tell from these articles, WebSocket is supported out-of-the-box.