Man, the bullet-train production speed of these Twilight movies is nothing short of mind-boggling. Not long ago, Dakota Fanning and Michael Sheen were cast as members of the antagonistic and powerful Volturi, a vampire coven introduced in New Moon who hangs out in Italy and polices the world’s vampires with red-eyed authority. Now the two are in posters and a movie that’s coming out in 80 days. Summit means business and are assembly-lining these suckers while the Twilight passion is …