Dave Grohl has sparked wild rumors of a Nirvana reunion tour after the band came back together for last week’s 12/12/12 Concert at Madison Square Garden. The shows would come 22 years after the group’s breakthrough album “Nevermind.” Sources tell us Nirvana drummer Grohl has been privately telling friends that he’s working on a “Nirvana anniversary tour with a secret frontman.” And we’re told that would not mean Sir Paul McCartney, who performed with Grohl and bassist Krist Novoselic at the MSG concert for victims of Hurricane Sandy. The charity performance was the first time the two surviving members of the ’90s grunge act have played together in 20 years. The move did not impress Kurt Cobain’s widow, Courtney Love, who said she was “not amused” and their performance was “bad.” But — before you get too excited — reps for Grohl dashed rumors of a reunion tour, telling us they are “nonsense.” We still live in hope this could happen. Our suggestions for the secret frontman: Eddie Vedder (whom Cobain initially disliked before they later became friends), Jared Leto — or even Courtney Love?