http://www.gaystoryman.com/ comes to mind...

also you can go to
http://www.web-legal.com/xtitles/full/TextAudio.html
and search for gay. there are several sets there.

there's a gay story bundle at ounique - search for Jcs0011-b

or you could hire someone like *ahem* basschick, bec or another of the fine writers on this board to do you custom stories, exclusive or not.