there is an interview where Stephenie talked about Henry. Here is what she had to say :-
I’m a very visual person — when I read a book, I usually cast it in my head as I go. So, long before I knew I was writing a novel, I was already casting my characters. My favorite actor for Edward is Henry Cavill (a little known British actor who played Albert, the teenage son in the most recent version of The Count of Monte Cristo). I feel really passionately about him getting the role, and, should I ever get a chance to talk to anyone about any aspect of the movie, his name will be the first words off my tongue. Of course, he’ll soon be too old for seventeen-year-old Edward, so that only applies if MTV Films gets to work on it in the near future.