Interactive Story
Story by Teozakeru
http://iiichan.net/stuff/be/dodge/
Found this on the net the other day. It's got some futa stuff in there too, but I have no idea how people add new content to it. It's been up since 1999, though.
Here's one of the futa segments. It focuses on Teen Titans, though there are original segments and other anime/game segments:
http://www.bearchive.com/~addventure/game1/docs/573/573027.html
Too bad the Fullmetal Alchemist segment is empty. :(