The practical problem with Palin is that she is under an ethics investigation (two, actually) for firing the guy who would not fire her sister's ex-husband as part of a nasty divorce, with the report due out shortly (Four days) before the election. I'm amazed that she made it through the initial vetting process.
http://thecaucus.blogs.nytimes.com/2008/08/29/palin-ethics-investigation/