Rumor has it that Heidfeld is in talks with Toyota (why, that is beyond me), which would imply that Toyota will get rid of Ralf. Given the fact that Toyota can be harsh on their drivers, it wouldn't surprise me if Montagny was asked to step in for a few races towards the end of the season.
What about Barrichello...well you can't blame him. I mean had it not been for team orders at Honda he would have been a champion by now (sorry, couldn't resist).
Heikki...really, really doubt it. Flavio was harsh, fans had been disappointed, but in all fairness I think that they all know that the blame should be pointed at Renault who seem to be struggling ever since the major changes had taken place at the end of the season. Besides, can you imagine how many teams would like to give him an opportunity to drive for their team.
Speed...now there is a safe bet. Berger isn't happy with him, and Speed knows it.