I was wondering if you were ever able to locate that copy of the family tree you were searching for. I've tried searching for a Patafio coat of arms but I never could find anything.
With regards to a possible papal connection, I did some research and you were correct about the name. Pope Pius IX referred to himself as "prisoner of the Vatican" after Rome was captured by the armed forces of the Kingdom of Italy in 1870. Someone else here also mentioned a possible connection to a pope and something about "prisoner of the Vatican", as well as a rumored link to the Borgia family. It's an interesting line of research, as I have never heard of such a link but it's always worth checking out.
Well, back to researching!