I agree with your final prediction but not with your reasoning. The United States will likely not allow Knox to be extradited, not due to a vague sense of reluctance or unquantifiable dislike of Italy, but because the US has explicit laws that not allow extraditions relating to double-jeopardy. Any country wanting to extradite someone due to a crime for which they have previously been found innocent will be ignored. So in fact, the US would actually have to find a procedural excuse to allow the extradition request.
but because the US has explicit laws that not allow extraditions relating to double-jeopardy
Well do those laws (and the decisions interpreting them) make clear what should happen in a situation where the defendant was convicted at the trial level; the conviction was reversed at the appellate level; and then subsequently reinstated after a further appeal and remand?
I don't think so. One article I read has a law professor asserting that double-jeopardy would not apply:
...Some legal analysts have said that Knox could cloak herself in the Fifth Amendment’s
Today an Italian court has declared that Amanda Knox is, once again, guilty. She did not attend that trial (is not required to in Italy), so her final verdict will be either by appeal to the Supreme Court of Italy or the US extradition court. Extradition requests might be impeded due to the fact US does not have double jeopardy.
Previously on LessWrong, in The Amanda Knox Test: How an Hour on the Internet Beats a Year in the Courtroom there was some complaint that it actually took more than an hour on the internet to thoroughly research the case. Of course, the courts have been at this since 2007...
Her co-defendant, Raffaele Sollecito, who did show up at the trial, got sentenced to 25 years, but I don't know for sure where he is now because apparently he's totally unimportant and who cares (the media's opinion, not mine). I'm fairly sure he's in Italy though. So far it seems the plan is to revoke his passport but not arrest him.
Anyone want to take their hand at making predictions?