I've never been here before but i just woke up from this dream after having the flu and playing left 4 dead. But anyways getting to the point,

Its a little bit of a cross over from Bioshock, but the idea is to replace the witch model with a dead body with a little sister harvesting ADAM from it. Same concept as startling the witch except, once you startle her, instead of the raging fast as hell witch tearing you up, it'll spawn somewhere in the area, a Big Daddy like any other special infected, which i guess would have the same AI as the tank. But with maybe half hp and half damage or something to be fair, i don't know.

But there you have it. I don't hold any claims or progress on this possible mod, anyone is free to take the idea and try their luck. Although if one of you bad enough dudes do decide to take this up, throw me a notice or something? I'd wet myself seeing it.