along the lines of "Upcoming niche" thread but more about the niche you never see within the Gay market and if you do see it, it's poorly done and the only one of its kind.

Sploshing (food, paint, latex)
Slap Stick (Tar and Feather, Pranks)
Clown porn (I think Ouchy is the only thing close to gay and he is "bi" from what I understand. Unless you count Ggreg Aka: Nam Blah the clown into the picture and he isn't in porn)
Costumes (superhero, church figures, Period, Sci-fi)
Horror Porn (Adding a theme to costume where all sets have demons or Monsters going to town on someone)