We don't actually. It's something I've thought about but haven't really put into action yet. I'd be more than happy to put up a poll to see if a Request board would be something people are interested in. My only hesitation with putting one up is that it leads to a lot of abandoned RP's because people will post up a million ideas 'cause they are bored, then they lose interest, ect...
But, it's up to the entire site to decide, not me alone.
Thanks for bringing it to my attention though...I knew I'd have to face the challenge of a request board sooner or later!
I am just hoping that people use it wisely to avoid a number of RPG's going to waste.