http://www.erotica-readers.com/ERA/G..._Fantasies.htm

Specifically mentions Master/slave as a possibility. They do ask for the story in the form of a personal fantasy but for a creative writer such as yourself that should be no problem.
They do not mention a specific story length but a 200 story printed anthology would want short stories in the 2-5 thousand word range, the tighter the better.

There are other possibilities look through both the print and e markets on the calls for submissions page.

hope you find the time

Mad Lews