Not going by nationality at all but here are a few other additions because I love those books.
Robb Stark: Max Aaron
Daenerys: Liza Tuktamysheva (those beautiful jumps are perfect for Dany!)
Oberyn Martell: Javier Fernandez
Who's Theon Greyjoy? Maxim? Nikita?
Hey, you LOtR peeps…pick a female, any female, for Boromir!