This is a very difficult question but if the Founding Fathers lived in modern times, what sort of Constitution do you think they'd draft? Given the same level of intelligence and the same personalities they had in their time but with the benefit of understanding modern technology, circumstances, and historical events? I'm sorry if I didn't frame the question as well as I could.
Can I presume that in such a scenario there is/isn't a pre-existing Constitution? If I know this it would help me answer the question.
If there isn't a Constitution before, the Butterfly Effect might change the issues that the Founding Fathers would feel necessary in the Constitution. Hell, the issues we consider important today might be different in such a scenario.