Zombie ☆ Gun
Well this moment was destined to arrive eventually. And this was the most obvious way to do it, because problems are always necessary in this kind of stories. We don't need a genious to tell us that Bakuman is coming to an end, 'cause it's quite obvious too that the two main objectives are about to be solved. And considering their last job (Death Note), I don't think they will make this continue after that. I think that once that two goals are achieved, this story will be in the perfect state for an ending. They have great ideas, but not the kind of ideas you continue for 500+ chapters like naruto, bleach or one piece. They work in short/mid duration mangas, and that's the way we have to prefer it, because that's what makes them SO good.
I think bakuman will be over before (or at) chapter 200.