Hi Scott,
This is Emre, your previous freelancer regarding to vSFTP monitoring project. I hope you are doing fine.
I just saw your project regarding to vsftpd limiting connections per user. I have some ideas to implement this configuration using the PAM authentication module.
Please drop me a line whenever you have time to discuss the project and even let me perform a small configuration on server to test what you are requesting. If it works then we can continue quickly setup it on server.
Thank you for your time and hope to talk to you soon again,
Best,
Emre.