Rufus Wainwright has taken to joining Ben Folds onstage lately to cover “Careless Whisper.” But even though the prospect of this latter-day George Michael and Andrew Ridgely is exciting, local Wham purists shouldn’t start inking protest signs just yet. Wainwright’s last stop on the tour comes just before Folds rolls into the City Market. Instead, maybe fans could emblazon some signs telling Folds to get his ass back in the studio to record another full-length album already and quit fooling around with this limited-edition-available-only-on-the-Internet-EP-trilogy nonsense. For the love of Reinhold Messner, it’s closing in on three years since Folds released the hooky, delicious Rockin’ the Suburbs. Ben Folds Live doesn’t count, although anybody who saw dude on the tour from which that concert record was culled can attest — from song to stage banter — the man does put on a wicked awesome show.