I took a look at the BVH spec, available here: http://research.cs.wisc.edu/graphics/Courses/cs-838-1999/Jeff/BVH.html
It seems like Leap Motion data definitely could be translated in to this format. Any conversion script would have to be written manually though.
Such a script would take in joint positions and bone lengths from our API, and calculate rotations from that. This data format is similar to what THREE.js and others libraries expect for rigged skeletons.