Hi, bkvamme, and welcome to the DonationCoder site.
Any chance of adding support for Plex Media Player? It has support for Media Keys, but needs the program to be in focus when pressing the buttons.
I'm pretty sure you're referring to the browser-based Plex Media Player, right? If so, and in my experience, there really isn't a reliable way to control these types of players remotely the way that MPH works. As an aside, I run a Plex server and love it's functionality.