NEW YORK (Reuters) – Madonna will be honored at the Billboard Music Awards show this month for her 2012 MDNA tour, the high grossing concert tour of the year, organizers of the awards show said on Wednesday. The singer will accept the Top Touring Artist award at the MGM Grand Garden Arena in Las Vegas on May 19th for the tour that grossed more than $305 million from 88 sold-out shows and attracted an audience of 2.2 million people. …