We are a startup [1] working in this space (hand tracking) for some time and it's been an interesting experience. Most of the hand tracking is done either using cameras (vision/image-based) or sensors (gyros/accelerometers).
Leap Motion is already developing a product similar to Nimble VR. Control VR intrigues me but my gut feeling is it'll be a while before their products are available on the market (see Myo band for example, it took a while for them to fulfill the orders and the product still has some issues based on the last hackathon I attended)[2]. Regardless, it's an exciting area (bit niche) but hopefully there will be a solution soon.
[1]http://www.breqlabs.com
[2]http://www.betakit.com/team-raisins-wins-sportshack-2014-tor...