I have no idea, where I could find more info on the web (for free), we have no local Family History Center I know of, and the real deal only seems to be accessible in Trento (as already mentioned by someone else, the microfilmed parish books of the church of Canal San Bovo in the office of the Bishop of Trento). I was hoping for a reply by Carlos Augusto Sperandio from Brazil, who mentioned to get in touch with him for more info on his findings, but there are no contact details of him, so it all comes down to this forum (although it does not seem as if he is still following this thread).
I do not speak italian, my mother went to some italian language courses some time ago, but she is far away from being able to have a fluent conversation on such a topic, but maybe we find the time to visit the mentioned Adriano Sperandio, and take him to the Bishop's office in Trento for some research.
I really wonder, how others were able to track back their ancestors to the 15th/16th century, considering the sparse info available the easy way.
Good luck anyway, maybe someone else following this thread can provide some more info, and share his findings as well.
Michael Rudolf Sperandio from Austria/Europe