This an extremely important point. What would be useful is if somebody created a mathematical model of the tax system. This model could drive these other sites

This an extremely important point. What would be useful is if somebody created a mathematical model of the tax system. This model could drive these other sites, and it could also be used in all sorts of "what-if" scenarios. I don't think this exists, and it seems like such an obviously good thing to have. I guess the problem is that there's not really a mathematical model of the tax system. Everything is subject to some interpretation, and the rules and system has become so complex that it is probably impossible to model. (Just answered his own question)