I have a HID backend mapping for Traktor Kontrol F1, in HID mode for mixxx 1.11. All buttons and LEDs are mapped to some function (but not always a valid function!), and the mapping still has plenty of debug messages: it's not finished. I have used this template mapping mostly to test I can control all brightness values, 7-segment screen parts and RGB colors of the PADs, not to actually map anything in mixxx yet.
This wonderful device is more for users of sample decks, and since I don't use sample decks myself, I'm not sure what is good mapping in mixxx for this controller.
So, for anyone interested working on this controller, don't reinvent the wheel, hard part of mapping the inputs and outputs in HID packets is done! To continue working on this controller, you don't need to understand HID anymore, that part is finished and tested.
Since I mostly work on HID support scripts right now, and will continue modifying this unfinished HID mapping myself, I don't post it to this forum thread. Instead, grab it from my hidscripts branch in https://code.launchpad.net/~hile/hidscripts and if you improve it, post here and I'll merge it back to this tree.