My favorite version of "Ain't No More cane on the Brazos" is in the documentary Festival Express, which follows a 1970 (?) concert tour of Canada, by train, of The Band, The Grateful Dead, Janis Joplin, and others. The film is a great document of a legendary tour and the cameraderie of these great musicians. At one point there is a scene during which an obviously very high and drunken group led by Rick Danko, Janis Joplin and Jerry Garcia sing a barely coherent version of the song that ends up coming out as "Ain't no more brain on the Cazos..." Very bittersweet, especially because all three of them have passed away.