I've got over 19 minutes of this. I knew a guy who said he had more but not quite all. He wanted an s-load for his films. Lives in Cambodia last I heard.
No, the theatrical version is the longest version. Mike Jacobs was notorious for leaving huge chunks of fights on the editing room floor. Billy Conn once asked him why he had so much edited out of the Conn-Louis fight (a lot of Billy's best moments are missing from the film) Jacobs replied "When YOU become a promoter YOU can decide how YOUR films are edited." He didnt like being questioned.
You may have over 19 minutes but that can due to a lot of things i.e. the speed at which the film was transferred, how much filler was added to a certain production, etc. Its extremely unlikely that anyone has any more actual fight footage than what appears in the theatrical version.