This is a bit late, but there is an excellent Teen Titans fic which I thought of as soon as this thread was first posted, and I finally managed to dig its name out of my records.
Family Affairs
http://www.fanfiction.net/s/1923629/1/
While this is a Teen Titans fic, it is not a Teen-Titans-TV fic; it's based on some form of the original comics' continuity, and involves far more characters than just the ones featured on the TV show. I don't know if the original request was implicitly asking for TV-show fic only, but regardless, this fic is good enough that I'd be remiss not to mention it.
Family Affairs
http://www.fanfiction.net/s/1923629/1/
While this is a Teen Titans fic, it is not a Teen-Titans-TV fic; it's based on some form of the original comics' continuity, and involves far more characters than just the ones featured on the TV show. I don't know if the original request was implicitly asking for TV-show fic only, but regardless, this fic is good enough that I'd be remiss not to mention it.