The rights for the Sam Mendes/Rob Marshall production of Cabaret are held by the Roundabout, not Tams-Witmark. So far, Portland Center Stage in Oregon is the only other company that has produced that version of the show. Chris Coleman, the artistic director of PCS explains it on his blog:
PCS is the first company outside of the Roundabout to have been given rights to this particular version. Not sure why the authors hadn’t allowed other folks to do it, but when we began asking - initial responses from the author’s agent was, “The rights are not available to that version. It’s owned by the Roundabout.”
I had happened to sit on the Theater Communications Board with Todd Haimes, the Artistic Director at the Roundabout, and thought that they probably wouldn’t care if we did it. But I had to get Todd to call the agent of the author (Joe Masteroff) and the agent of the Composers (Kander & Ebb) and say, “We don’t have a problem with PCS producing our version.” Sounds simple enough but it took about four months of consistent nudging to get all parties involved to say yes.
Chris Coleman's Blog