Ok, some of you will think I'm a complete perv for thinking about this, but I have an idea for a game called "Naked and Bulletproof", with a "hentai" theme (anime porn, for those that don't know).
It would be a card and board game. Each character would have a series of 10 cards that featured them in various states of progressive undress, and that is how you track their HP. The more damage they take, the more clothing they loose. Then when they are completely naked, they are invulnerable, but can still go around attacking other players. Then the last one with any clothing wins.
There would be different boards to play on, like a school, house, and other such locations, and players take turns moving and attacking using cards drawn from a shared deck. There would be other types of cards in there too, like defense and healing, but once you were naked, you couldn't heal any more.
I know, a real pervy idea for a game, but one I've been thinking about. :)
Hentai is one of those interesting topics that fills an odd grey area thematically. It's hugely successful, and even anime/manga that doesn't overtly fall into the Hentai genre often creates provocative images and characters suggestive of Hentai.
It actually sounds like a more interesting/salable idea than Phil Foglio's XXXenophile, which featured both poor art and poor gameplay. And while it's a fringe idea, and would certainly not appeal to everyone, I'm sure there would be a market for such a game -- especially nowadays when folks can purchase such a game via the anonymity of the internet.
Good luck with developing this idea! You may have more on your hands in terms of up front development to really get this to a polished product, but it may appeal to the same sorts of companies who import anime and hentai videos, as it obviously ties in to their target market base.