Natalie Portman Cast In Marvel's Thor?

Nikkie Finke has been on a roll regarding news from the world of Marvel, which makes me think she has a good inside source. Today she posted a bunch of casting tidbits for Kenneth Branagh's Thor. First up is Thor himself. Finke gives a list of actors who have tested for the role, including Josh Hartnett, Charlie Hunnam (Sons Of Anarchy), Tom Hiddleston (The Gathering Storm), Liam Hemsworth (The Expendables), Joel Kinnaman and the previously rumored Alexandar Skarsgard.

But the big shocker is that Natalie Portman will be playing the lead female role. Possibilities after the jump.

I can picture Portman as Option #3 but that wouldn't be the most logical choice considering that most of the film takes place in Asgard and not in the modern day real-world (or at least from what we've heard). I doubt that Portman would sign on for a small role, but maybe she did't sign on just for Thor and her part would pay off in The Avengers? I just don't see Portman as a Goddess or Enchantress, despite the fact that she did play a Princess in the Star Wars prequels.

While I consider myself somewhat versed in the Marvel universe, I have only really encountered Thor in The Ultimates. So my insight into the possibilities are based only on what I can gather from comic book websites and wikipedia. Maybe someone more knowledgeable in Thor history will be able to offer their expertise in the comments below.