Ha, I'm currently using FVP and started at around AutoFocus 2. It's not enough for all of what I do, but perfect for the crucial stuff. I've also been thinking about building my own tool that implements this. Let me know if you have something!
The app I'm working on is not a strict to-the-letter implementation of Autofocus / FVP, but it will certainly lend itself very well to similar systems. I'll let you know when I have an MVP to test.