I think the fact that Trump is not going to ever declare his candidacy will remove any hunt for the Trump birth certificate. I think he is using these presidential hints as a way to promote his show. After it completes it's run, we won't hear a thing about Trump the candidate again.
The weird thing is that the Republican field is so weak that Trumps points about China were actually wearing pretty well. He almost could be a legit candidate if he stuck with that, but the birther stuff gets more publicity, which is why I think his candidacy is merely promotion for his show.
I always assumed that since Trump's show is on the NBC network, these rumors of a presidential run in 2012 were a mere smokescreen by the Obama administration and the liberal network to project republicans as extreme right wing buffoons with wild agendas only the crazy would love in order to deligitimize the republican party.
Now that's a conspiracy theory!