You should read Fred Bauer on the homepage today about Romney underperforming McCain among the working class.
Also, this New Republic piece is interesting, regarding the regional concentration of Romney’s increased white support:
Romney’s strong national showing among white voters was almost exclusively driven by historically strong support from southern and Appalachian white voters. In many counties, Obama’s performance was the worst by any Democrat since McGovern or, in some places, the worst ever. Even a quick glance at overwhelmingly white, southern, or Appalachian counties with a history of offering even limited support to Democratic candidates shows Obama performing anywhere from 15 to 30 points worse than Kerry did eight years ago. Obama even lost more than 50 points compared to Kerry’s performance in several “coal country” counties in southern West Virginia and eastern Kentucky.