It's been done here and there. A few comics by
CastleDolphyn and
KannelArt, and some stuff on
TG Comics.
I had a concept along those lines too, though I never did much with it beyond a half-finished sketch. I called it "Princess Town," and it takes place in a segregated city where the government consigns men who have succumbed to an ailment which turns them into cartoon women (usually princesses). The protagonist is John Maleficent, and the story would follow his/her efforts to solve the murder of a Sleeping Beauty he recently romanced.
Now that you mention it, I'm slightly surprised that it isn't done more often, though I guess it's because Noir fiction depends on certain elements, like atmosphere, scenery, dialogue, motivation, and character, and these aren't often really emphasized in our rarefied subject matter. At least, not all at once. The Noir aesthetic kind of has to exist for its own sake, with a heavy emphasis on a "down" mood which is rarely combined with the usually "up" attitude of fetish art.