Sure, there's been talk, but your understanding of the law is incorrect. You have to be a "natural born citizen" which can either be accomplished by place of birth or by the citizenship of your parents.
The place of your birth is not determinative if it's outside the US.
These threads will get interesting when they actually start to allege that Obama WASN'T born in Hawaii and offer proof of where he was born.
But it still wouldn't matter because he's a natural born citizen because of his mother.
The fake birth certificate at KOS is interesting, but it's not really even relevant.
Not just talk, there is currently a court case challenging this very fact.
The Senate took it upon itself to vote that he was indeed a natural born citizen, however the courts have never ruled on this, and it is a constitutional issue, which the Senate can not arbitrarily decide.
I predict no court will touch the issue either before or after the election. It may come up as an issue at the convention, which may be what this is really all about. Time will tell, I guess.