Will VA (R) and North Carolina (D) ever again split in the opposite direction?

[Skill and Chance]

Just FTR, are we all completely resigned to the idea that NOVA is forever Democratic?  It was once the only Republican friendly part of the state, and it's not like it's necessarily been THAT much more liberal than VA for a long time (ala Chicago in IL) and is finally turning the state because it's big enough (like Chicago did to IL).  Pretty much pre-2004, it was SAFE GOP territory.  I think Obama was a good fit for the area.  I'm not saying it'll come back in the near future or anything, but the idea that it will eventually trend VA to become the next IL or NY is a bit out there, IMO.

Look at what has happened in MD since 2004.  It has now gone from about D+7 to about D+11.  And most of that change has come from the immediate DC suburbs blueing.  I don't think anyone believes VA will be D+11 in the 2020's, but there's a clear precedent for it to keep moving left, perhaps to an Upper Midwest level of partisanship.  I also expect that any future federal GOP effort to balance the budget will only accelerate the trend and could easily drive the DC suburbs from 60%D to 70+%D.

So I would say that NOVA is not coming back to the GOP.  The rest of the state could if they can figure out how to get >20% of the black vote, though.   

[Skill and Chance]

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.

I'm not convinced about your first scenario.  I think that only works if the Democrats would have to be in full control federally at the time of the collapse.  Because if they weren't, they would just campaign on restoring as many of those lost jobs as possible.  It's difficult to imagine the Republicans outbidding Democrats in an effort to grow/stabilize federal jobs.  Some would leave for sure, but those who stay would be more unanimously Dem than they are now.  The DC area in a default/bankruptcy would be like Detroit in 2008 or Oklahoma in 1932.