Carl Spielvogel, who rose through the ranks at Interpublic to become vice chairman before resigning to form Backer & Spielvogel (with partner Bill Backer) died Wednesday in New York. He was 92. An assistant to Spielvogel's wife Barbaralee Diamondstein-Spielvogel confirmed the death to the New York Times. Backer & Spielvogel, launched in 1979 got off to quick start, landing Miller beer within three months and creating the iconic "It's Miller Time" tagline. Saatchi & Saatchi later bought that agency and merged it with Ted Bates. Spielvogel, a self-described "streetwise Brooklyn guy," was later appointed U.S. Ambassador to Slovakia during the …