I hate to throw cold water on this, but I seriously doubt that there are a lot of "forbidden" works that are locked away in the basement of the Vatican. It takes work, but researchers can view almost anything they have. What the public is kept out of, if anything, are documents and records that could be damaging to the Roman Catholic Church.
I am no lover of the HRCC, but I think this theory is rather like the legends that the Knights Templar became the Scottish Masons and still rule America from behind the scenes.
In short I should have been from Missouri. Show me some evidence, because I don’t believe without proof.