I don't know if one person or one hundred people have been responsible for Mesa 2. However, if you need support, the line goes through Dan. His home page is home to the Mesa 2 AddIn Object Kit and the Mesa 2 Toolbar Customizer. I'm letting this serve as a timeline of reviews and news about Mesa 2. If you have some links to add to it, let me know.
Contributions are always welcome.
Let me know if you have any explanations or snippets of code to contribute. This my a description of what the AutoFormulas do. It uses the AutoSum button as an example. It's cool, and I think it's on the mark. This is my set of custom spreadsheet functions for Mesa 2 2.2.