Here's what I can tell from watching her speak in Latrobe PA on MSNBC: She doesn't have an actual accent of her own. It's like watching Cameron Diaz trying to keep up an English accent in a movie. She goes back and forth between Broadcast Standard and some mutant form of Upper Midwest. She's not from Duluth, why does she try to talk like she is?
But the kicker: In Latrobe PA, she was talking about 'Still-Workers.' That long-'e' to short-'i' vowel shift is specific to that part of Pennsylvania, near Pittsburgh. WTF? Does she travel with a dialect coach?
[EDIT] Just because your LJ is supposed to be all multimedia, and I love this image so much: