Kristin Chenoweth could definitely pull it off acting-wise. I can't really see her with dark hair, but that's the least of our troubles.
Cristina Ricci could do it, but Im not familiar with any of her acting, so I cant really say.
I'll edit this post when I have any new ideas, but so far, Im coming up blank.
Im breaking up with you. I took you to the beach and you didnt even sparkle. So give me back my copy of Eclipse before I punch you in the face. Youre no werewolf, either.