Hi,
As I understand this you don't need steam to connect to a server? The reason I ask is I can adapt my game server (a game I am developing) to work with the RCON format.
I have tried to get it to work with my host who swears that my ports are open with no success. I know my firewall settings, virtual server (router hole punching) and ports are all in working order as I wrote the game server and clients and they all connect from around the world. I have even made sure that PHP function fsockopen() is enabled. I have also written a little app to poll the port in question and no data is received from the hosting service.
So that's where I'm at. Would be cool to get this working. It looks entirely possible to use this for a non steam game as long as I support the RCON format.