Maybe give it some time. Apple is already allowing age restricted apps now that iPhone OS is capable of parental locks. Currently, the rating goes to 17+ with nudity as an available content descriptor for the US, but, so far, only apps going as far as bikini and lingerie models are being approved. I have seen an app out that has Jenni Gregg, Lillianne Tiger, Monika Sweet, Lucky and Jana Cova in it.
Their policy actually is actually against pornographic content, but you can have nudity without it being porn. I guess it's just up to their interpretation.
Like I said, give it time. Maybe they just need to figure out where to draw the line.