Um hows about the Wisconsin recall, or Scott Brown in Mass. Both of these polls were 8 and 6 points out of whack on election day.
I don’t know what polls you have seen, but RCP could not have been any closer on the Walker recall.
http://www.realclearpolitics.com/epolls/2012/governor/wi/wisconsin_governor_recall_election_walker_vs_barrett-3056.html