The EMI recoding of Showboat is indeed terrific. 3 cds and a large booklet with every known piece ever written for Showboat including the songs written for the 1936 film version with Irene Dunn, Helen Morgan and Paul Robinson. (I recommend that highly too.)
Does anyone know if the McGlinn version was used in the last big Broadway production produced by the notorious Garth Drabinsky? Both were controversial because, as with the original, the show opens with the chorus singing "Niggers all work on de Mississippi".