I don't know about the MySQL backend...that would work for me, and probably you, but who else? How many people really want to install and troubleshoot (and maintain) a MySQL instance just for this?
Although, while thinking out this post, it may work to have a hosted service, where some of us go together and pay for the hosting. With a web front end, it eliminates the MySQL problems, but doesn't keep it free. I guess I will take a peek at the source and see how tough it would be to put a PHP front end on top of a MySQL backend; once I get all my servers move out here to OH, I will have an easier time of setting this up.