1 - See the RNC memo (granted Ohio has it's funny registration process)
http://www.nationalreview.com/campaign-spot/331501/rnc-check-out-our-early-votes-swing-states2 - Romney will win more undecideds than Obama, as challengers often do.
3 - Pollsters, whatever they are doing, are misjudging the type of electorate or having a response bias of some kind that skews democratic. A D+7 or 8 sample (regardless of the pollster not actively modeling this) showing a Romney lead or slight loss means that Romney will win. The electorate will not be as heavily democratic as it was in 2008.
4 - Romney has the momentum going into the final days and a tie debate and a slight Obama win on foreign policy debates did not make Romney an unacceptable alternative in the eyes of the electorate.
5 - A silent majority.
6 - The venue chosen by Obama to hold his election night win/lose speech.
7 - Active panic in the media and in Obama's campaign.
8 - Locally, he's been up here trying to shore NH up way too much for them not to be worried.