Somehow, I don’t think we’re going to hear anything. If Mercedes want Hamilton to replace Schumacher, they’re not going to announce Schumacher’s retirement when McLaren have just announced that they are willing to match Mercedes’ offer to Hamilton. Doing so would only give more bargaining power to Hamilton, and as much as the team might want to keep him, they’ll be reluctant to cede any more ground to him. And it’s not good for Mercedes, either, because if McLaren are willing to match Mercedes’ offer, that suggests that Hamilton hasn’t signed anything with Mercedes yet.
So I suspect that we’re only going to hear something if it’s along the lines of “Hamilton to replace Schumacher at Mercedes” – ie, a whole driver move, not half a one like Schumacher leaving.
Nobody moves. Not even Massa. Everybody wonders why. Why, Ferrari? Why? Schumacher is only committing on a year-by-year basis after having a frustrating season of some limited success and a lot of disappointment. Force India and Sauber keep their drivers who are often speculated as on the move (although maybe Kobayashi is kicked out). Why, Ferrari? Really?
I, too, have the feeling that this whole potentially spectacular silly season will all end in a stalemate. When Webber resigned for Red Bull the first door was closed and I imagine that, as @matt90 said, Hamilton, Massa and Schumacher will stay put, keeping the Force India and Sauber drivers (Kobayashi as well) in their spots and so also blocking Kovalainen and/or Glock from moving (back) up the field.