Alaska only has 700k people. Smaller budget, unique problems to be sure, but still a small constituency. Governor/Senator=wash.
I think its a despirate bold move. But I don't think it will work.
Actually, since Obama has been running for President nearly since he became a Senator, while Palin has been at home in Alaska minding the store, I'd say her experience trumps his, by a long shot. She was also a mayor of a small town before that.
It's not necessarily the size of the constituency, but rather how well you represent them and how hard you work for them.
Oh, and Obama's whirlwind "See, Europe and the Middle East LOVE Me" tour does NOT count towards foreign policy experience.