LUXE MAGAZINE publishers Jason Binn and Brian Greenspun are teaming up. Greenspun, whose titles include Vegas, Wynn and Venetian Style, is pumping cash into Niche Media, whose holdings will include Binn's ad-fat mags Gotham, Hamptons, L.A. Confidential, Aspen Peak, Boston Common and Capitol File. Staffers say they've been assured that their jobs are safe.