I developed a completely free and open source Ruby on Rails version of formspree a few months back. I made it because I was looking for something similar but without the security and privacy concerns I had with formspree. Unlike the formspree on github, my app has no paid dependencies and has complete configuration instructions for users who want to self host on heroku.
Read about it here: https://github.com/jtlindsey/EasySWFSender
I haven’t had much time to work on it but it is production ready and easy to follow if you know rails.