I'm not sure if what you are asking for exists. That would be cool because there seems to be a forum for every niche out there, but it's hard to tell which ones are the best or most active.

If you find anything please let me know.

edit: After I posted my comment I found this wiki page http://en.wikipedia.org/wiki/List_of_Internet_forums. Though it doesn't have a photography forum, the list is interesting.