[lincolnq]

Anyone want to start one?

The project is not easy. It requires carefully reading tax codes and implementing them, handling presumably thousands of explicit legal requirements plus whatever edge cases exist that may or may not be explicit in the law. Not to mention keeping up with annual changes. If you screw it up, whether or not you are legally liable, people are probably coming after you anyway. And the support nightmare...

That said, I think a programming-languages approach might be a good one to try to execute on this. Keeping the source code as close to the tax code as possible seems the only way to stay sane with respect to long-term maintenance.