Castellano (probably) was the last one. After the Commission case, the Commission ceased to exist. So neither Gotti or Gigante were chairmen. The Gotti/Gigante meeting in 1988 was not a Commission meeting. The one in 2000, which was hosted by Massino, is debatable whether it can be considered a Commission meeting or not.

There are overwhelming information, testemonies and evidence of the existence of an official chairman. How can you deny that? Pick up some books and read up on the matter. Off the top of my head, my first suggestion would be Bill Bonanno´s latest. There are no reasons for him to lie about it. If the existence of an official chairman only existed in Bill´s mind, he would have made the laughing stock by Mafia experts, LE and others in the know. You can also go to the Mary Ferrell site and read documents about it. To be honest, I feel it´s kinda ridiculous arguing with you on this. It´s like arguing with somebody who´s denying the existence of the Mafia. Over and out.