Good info everybody...Here's another long serving "Official" Family boss - James (Jimmy the Hat) Lanza.

If I'm not mistaken, I believe that Lanza was named the "Representante" of the San Francisco borgata around 1961. And although its debatable how active this Cosa Nostra network really was in their later years, Lanza was still believed to have technically retained his official title, as the "Boss" of San Francisco, until the time of his death, in 2006.

Thats a 45 year tenure...not bad!