Lyrics: Robert Hunter
Music: Elvis Costello
Hunter referred to this in an interview in Rolling Stone on 25 September 2013:
Elvis Costello and I wrote a [still-unreleased] song called "Tomorrow Blues."It's possible that Elvis Costello performed this on 6 October 2012 at the 6th Annual Richard de Lone Housing Project Concert. Setlists have a song called "Tomorrow's Blues." It was reported as the premiere of a new song, so I doubt it was a cover of the Coliseum song with that title. But I can't find any further details.