My name is Greg and I am the author of Driver4VR. Software that provides a way for body tracking with other devices than Vive, like for example Kinect or NoloVR Controllers.
Body Tracking is now possible only on PC version but we could get it easily for Quest with some simple socket protocol over wi-fi. It can be either open source or dedicated to VRChat. Of course, developers would not need to bother with protocol directly but we would write some wrapper for that for c++, c#. Same as currently OpenVR API.
I am working currently with SlimeVR team to use their protocol based on websockets with other methods of tracking like Vive Trackers, Kinect, Nolo VR, Webcam, PS Move in VRWorkout app. Once demo is done we will try to formalize those and make available to everyone.
What do you think about that? Perhaps someone from VRChat team would like to be engaged in this?
Best,
Greg