I guess the only way I could see this happen, with Romney winning the Pop Vote even rather handily is he blows out Obama in Texas and the South by epic margins...which is likely. A black democrat in Alabama, say, is more conservative personally and religious than your typical Chicago democrat. In fact, some southern Democrats, at heart, may actually be more personally conservative on a lot of issues than some northern moderate Republicans.
The point of that is I can see blacks staying home in Alabama, Miss, Georgia, South Carolina etc because they know Romney will win, and are disillusion with Obama.
Romney could then get REALLY CLOSE in PA, MINN, IOWA and still lose by a hair. Lose Wisconsin and Ohio by 1,000 votes and be a lot closer in California,, New York, Washington and New Jersey than McCain in 08...with Obama still getting the EVs.
With a little vote fraud in Ohio, and razor thin losses in a few states, you can make a fringe case for a Romney Pop Vote win...by a decent amount.... with an EC loss.
I don’t think that will happen, but it would be quite a strange time indeed if that happened.
But then you have stories like this where a 108 year old decides to start voting for obama. The enthusiasm on both sides is insane.
http://www.islandpacket.com/2012/10/26/2258223/108-year-old-beaufort-woman-first.html
That 1876 result really shouldn’t be included because of the particular circumstances of Reconstruction (as explained in the linked wikipedia article). A split of EC and popular vote probably only happens with a popular vote differential of less than 1.0% (as in 2000 and 1888).