After some discussion about configuring the Sink on Windows, I finally took a close look at the situation. What I found is not good. While Windows has included a driver for USB CDC-ACM since Vista, for some inane reason, versions older than 10 don't load it without an INF file listing each specific USB VID/PID pair that needs the driver. Also, Windows 8 requires this file to be signed. As of now, there's no way I'm going to pay for a code signing certificate just to tell an operating system to load a driver for a standard protocol that it provides itself. This project just isn't profitable enough for that to be worth it. If I was shipping a hundred units a month I'd probably do it, but somehow I doubt that will happen any time soon.
So, if you run Windows and want to configure a PD Buddy Sink, either make a live USB Linux system to configure the Sink with, or get Windows 10.