He's free to run for President, just not in 2016... I think he'll either try for his old seat again in 2016 or 2018, run for Governor in 2017, run for Senate, or run for President in 2020 or 2024.
If Rick Santorum could be viable in 2012, than Cantor could be viable in 2020 or 2024 (Assuming he doesn't lose another for the same or a different office).
Uh, what is his base supposed to be? The establishment isn't going to back someone who never held statewide office for president, and the Tea Party is obviously a non starter since they're euphoric about getting this guy's head on a platter.