I don't think Vettel is in any rush to switch teams. Even if his contract ends.
Given Ferrari's strategy issues and reliability problems, I don't think any driver wants to drive for them next year. Maybe not even a year after that. For a team to be desirable, it has to prove that it can show results and make the best of given circumstances and different drivers. And a team has to have to go on a run for a couple of years first for it to be desirable. When Shumacher was in Ferrari, they were desirable, because it seemed Ferrari are just amazing. Now, not so much. They just need to prove themselves for a while first.
For McLaren, drivers might not lean that way as well. They did very well last year, and this year they are ok on the track. But there's too much backroom drama. And I don't think any driver wants the distractions. All he wants to do is to concentrate on driving; not this lawsuit and that penalty. If the team is incapable of creating a good environment for the driver, the team isn't desirable at all.
If a driver knows the teams limits, and knows the team is doing its best and not letting the driver down, then the driver won't be as inclined to switch. Even drivers want to create the underdog dream. Knowing that the team is capable of better but not showing results is only going to make the driver feel he could be better elsewhere.
So, I personally think, there won't be much move from Vettel. It's not that he doesn't want to 'upgrade' to a better team, it's that the current climate is showing that RBR is the better team, if only because the other 'better' teams are doing so badly.
Hamilton might move somewhere. Partially because of the team problems, but more importantly because of his father. Did you all notice that Hammy's dad was looking very out of place and very stiff in the Shanghai race paddock? There is a lack of trust in the team. I doubt he'll move to Brawn. The biggest possibility for retirement is Barichello, but with the car doing so well, and his health isn't an issue, I doubt he'll want to leave. Especially when he has a championship chance. Button even less so. He might move to Renault because Piquet really needs the boot. But the problem with this is that Hamilton will be the second driver in Renault. For a world champ, that is less than desirable. I think he would prefer to be the first driver in a smaller team than the second driver in a bigger one.
Bourdais seems to be on shaky ground as well. He has a good record in other races, but Formula One just doesn't seem to be his thing. Especially when Buemi in his first year is doing much better than Bourdais. The contrast shows.
Does anyone have a list of when each driver contract ends?