I like the idea, but I don't want it to be too exclusive. If I were going to set up a system to control access, I'd say give access to anyone who PMs a moderator requesting it. Of course, if it were hidden, you'd have to know it exists first, so most of the noobs who show up on the forums would never know about it. If someone who knew about it saw someone who they thought should be in it, they could just send the new person a PM letting them know about the special subforum, and how to get access, so it would spread by word of mouth. Inevitably some noobs and trolls would get in, but they would be few enough that they could just be ignored and would learn to go away. (Of course, for this to work, we'd want to set up a general policy of "ignore trolls".) I like this idea much better than something more exclusive, because in my experience private subforums promote insularity and are reluctant to let any new blood in, even if that new blood deserves access.