Yeah, there was a nude patch for L4D. No, I didn't try it. Yes, I saw some screenshots. Zoey is right: It is sort of creepy. Her pants are missing but she's still got her jacket and her gear. She looks more senile than sexy. Now that I'm thinking of it, a mod where all four survivors run around without pants would be unstoppably hilarious as all of their in-game banter took on twisted double-meanings.
It's unusual to see nude mods for a strictly first-person game, since by definition you don't see yourself. This means that you'd have to jump into a game and leer at someone else being Zoey. The last thing I would want is for one of my gaming buddies to inhabit the body of a naked girl. That can't be good for either of you.
But now when I jump into a game and end up being Zoey I have to wonder: Does this guy have the mod? Does he see me naked? Is he really covering me, or just staring? Why does he always make me go up the ladder first?