It could happen, but it would depend more on events affecting Virginia than North Carolina. There is a scenario other than an attack on the nation's capital and Northern Virginia that could throw a wrench in Democratic chances in the Old Dominion: What if the United States went bankrupt and the federal government cut a significant number of jobs? Now, I'm not saying this will happen soon (surely not by 2016), but this kind of event could definitely occur in the long term and cause significant population loss in NoVA, the most Democratic area of the state. North Carolina would probably be adversely affected, but since it doesn't rely on the government to the extent Virginia does for providing jobs, it wouldn't see as much of a change from its current trajectory. In this case, North Carolina might be able to stay Democratic and Virginia could start voting Republican again. Of course, that would also depend on who the blame was laid on regarding the nation's bankruptcy, but I would forsee it as being equally placed on both major parties.
Another way that Virginia could go Republican and North Carolina could vote Democratic in the same presidential election is if Republicans had someone on the ticket from Virginia while Democrats had a candidate from North Carolina. Still, that would necessitate Republicans winning Governor's Mansion or one of the Senate seats in Virginia first, and barring any crazy circumstances, that can't happen before 2016.
Other than those cases, Virginia should consistently be to the left of North Carolina for quite some time.
John Edwards vs Bob McDonnell 😃