In one of the comic book stories he was a crippled doctor. I don't think he was ever "scrawny." I don't think that's the origin story they're using for the film, anyway.
Yeah, that's it. Sorry, that's just the origin version I remembered so obviously not the same here.
I don't have the old Journey Into Mystery comic, but I believe Donald Blake was a doctor with a lame leg. The story is something along the lines of Thor being banished to Midgard (Earth) and I vaguely recall him being trapped in Ice or something. Blake finds him or rather the stick I think and uses it as a cane. When the stick is slammed to the ground it turns into the Hammer. Blake goes off into some void and Thor appears. Likewise, when Thor is done fighting off baddies, he strikes the hammer to the ground. Blake and the stick return, Thor and the Hammer are back in the void. It's very similar to the Hulk concept when you think about it. The early comics also introduced the idea that if the hammer was away from Thor for more than 60 seconds he would return to being Blake, but who knows how much (if any) of this they will keep in the movie.
Since they already have Thor's hammer alla IM2, I'm betting they go with the sword-in-the-stone bit. It was said that no one but Thor could ever lift the hammer except in times of great need (a handful of marvel U characters have used the hammer when Thor was incapacitated). I bet they have trouble lifting it and somehow Blake is the one to do it.
