Trump is the ultimate "strategrist" [Thanks Pres. Bush]
I believe Donald has a bunch of facts about Obama in his hip pocket. It's not just "birther" stuff. He consistently refers - obliquely - to Barack's relationships with Resko [sp], Ayers, foreign governments, illegal fund raising. Now is not the time to reveal what he has - it's all about hole cards!
Trump certainly has the means to mount a first class investigative effort. More importantly - he has connections - prominent business figures for one!! I wouldn't be suprised if he has some volunteer assistance from folks like the Mossad, the Saudi's, the Brit's.
It will be very interesting to see when he elects to start playing his cards. I'm still on the fence as far as his chances - but Donald is nothing if not Formidible - far more capable than the others running on the right!!