Ben Affleck’s next costar might be Kristen Stewart (above). Variety reports that the Boston actor-director — who’s been out supporting Elizabeth Warren with his pal Matt Damon — and the star of the “Twilight” franchise might pair up for “Focus,” a movie about a grifter who finds a new, younger partner. Ryan Gosling and Emma Stone were supposed to be headlining the project, but Variety says they’re out. “Focus” was written by Glenn Ficarra and John Requa, of “Crazy, Stupid, Love.” Affleck wrapped “Runner, Runner” with Justin Timberlake just before getting on the road to promote his latest hit, “Argo.” Maybe Affleck will convince Ficarra and Requa to film “Focus” here. We wouldn’t mind a few Robert Pattinson sightings in the area.