I am sorry, I simply skimmed most of this thread so if this has been brought up then... I am sorry again :D
Have you ever read much of Isaac Asimov? He wrote a series of books called Foundation which talk about something very similar to this. The books the hero, Harry Seldon, is a brilliant mathmatician who invents a whole new branch of math called Psycohistory. It is the study of peoples reactions to events. What he can do is convert a bunch of events (involving humans) into numbers, write an equation for it. Then if a similar event occurs, he can simply change some variables and the equation will give him a prediction of what might occur. I didn't read the whole series, only the first book. But in order for Harry to get his project off the ground he needs to learn alot about human psychology. He needs to study history carefully and try to figure out how humans have acted in various situations. This story takes place in the distant distant future I beleive in the year 20,000 AE. A universe where the Earth is not only long gone, but long forgotton. In Harry's world even bringing up the idea that ALL humans came from only one planet is absurd. So there a few million, or maybe couple hundred million years of human history and psychology for Harry to study.
What you are talking about is very interesting indeed. As for your question of where to get all this knowledge, I will say it might be possible but like Isaac predicts, not for a very long time. I don't think the human race has set enough precedence yet. Maybe when we are a much older and wiser species something like this will be possible.
But it also brings up many questions of free will. if predicting what people will do becomes a part of culture then there will be people who will do things against what they are predicted to do...
