I believe one underexploited cinematic microgenre is the wonderful world of gay pulps. These were gloriously sleazy, about as un-PC as can be, and still ripe for movie versions. I see a mixture of noir elements, exploitation movies, and efficient but stylish Roger Corman flicks. A couple of ideas to get the ball rolling:

Never Been Rimmed. This remake of the Drew Barrymore vehicle Never Been Kissed sees a twinky twenty-something reporter going back to high school undercover on assignment. He befriends the varsity quarterback, a smug and totally straight jock, and then cruelly teaches him a few things about life, humility, and the pleasures of the prostate.

Sigmoidoscope! In this harrowing eroto-medical extravaganza, a nerdy fag orderly at a grimy public hospital (think St. Elsewhere meets Dennis Cooper's Horror Hospital) gets his sick kicks impersonating a doctor and performing unnecessary rectal exams on unsuspecting straight boys. Squirm delightedly as various tubelike insertables are used to rock their worlds! Special cameo by Harvey Pekar as the listless file clerk.