Nope ! Not one. I live in the Peoples Republik of Maryland. There is no such animal. In fact I have seen plenty of Obama 2012 bumperstickers and only one Romney sticker. Interestingly enough there are a handful of Ron Paul loons still out there.
You need to keep a few of these notes handy to leave on their windshields.
I don't expect to ever see conservative or GOP bumper stickers in 'Rat areas (and few in any areas).
The reason the leftists embrace destructive criminals like the OWS types is to intimidate decent people from expressing their views.