From what I have been told, the core designs were acquired by Ebonite in the take over of Track/Columbia. Also, a royalty was paid to Mo Pinel each time a core that he designed was used. As far as bringing back multi-density cores, the same numbers can be achieved from single density cores. I think days of the multi-density cores in the old Track are gone. That's not to say that another company couldn't produce a core similar in design to the old multi-density cores in the future, but I think that is unlikely for the most part. This may have already been discussed in a previous post, so I apologize if I stepped on anyone's toes.
