Basically, this article makes an argument that the 5th Amendment (in its current interpretation) has already implicitly repealed the natural-born citizen requirement for the U.S. Presidency:
http://repository.jmls.edu/cgi/viewcontent.cgi?article=1287&context=lawreviewAs for my own thoughts on this, I would say Yes. After all, if one embraces the idea of a "Living Constitution" (as I myself lean in favor of doing), then I see absolutely no reason as to why exactly earlier parts of the U.S. Constitution should be incapable of being implicitly repealed by later parts of the U.S. Constitution.
Anyway, what exactly are your own opinions on this issue?