Amanda Bell at the Twilight Examiner has a fun post about rumors regarding the casting of two additional vampire roles for Breaking Dawn as seen on IMDB’s Breaking Dawn Part 1 and Part 2 pages:
The first is Drew Roy, who the site notes is “rumored” to play “Nahuel.” That character, if you can’t quite place the name, is the one which [*spoiler alert*] which comes in at the very end as proof that “Renesmee” wasn’t the only one of her kind in the world and that she would grow up to normal size like the mortal that she is. As the Twilight Saga Wiki points out, ”Nahuel is described as an extremely handsome young latin man with rich dark brown skin, eyes the color of warm teak, and extremely attractive features. He wears his black hair in braid past his shoulders.” Drew Roy is a film and TV veteran of Hannah Montana, Greek, and others, and you can check out a picture of him here.
The second is Guri Weinberg, who IMDb.com has listed as “Stefan.” “Stefan” was one of the two Romanian vampires who had a particular distaste for the “Volturi” and hoped to see them fall once and for all. Per Twilight Wiki, “He has black hair and dresses in all black.” Guri Weinberg has been in films like Munich and You Don’t Mess With The Zohan. A good photo of him is available here.
Check out her complete post here. Until there is official word from Summit, just remember that these are both rumors.