And for a person? 6' 6" is outrageously tall, and that's who's going to be playing Thor, a person, not a drawing that you can draw as tall as you want. I laugh at the people who, for some reason consider height THE most important aspect of a character and will disregard anyone who isn't that tall regardless of acting ability or even looks, and then suggest some steroid freak wrestler.
The truth is, even if someone is like 5' 7" they could still play Thor, and play him well. It would be a shorter Thor, yes, but Thor nonetheless. By the way, comic book characters are all caricatures with rippling muscles weighing over 300 pounds and are 6' 3"+, but that's all it is, a caricature. When you translate that into the real world things aren't going to be nearly that extreme.