Leap Motion recently released their Orion SDK to developers. Orion is a software improvement that brings improved accuracy and reduced latency to the Leap, it's targeted specifically towards VR.
Orion only officially supports the Oculus Rift, and provides an SDK for Unity. While amazingly accurate and fun without a headset (I resorted to holding the Leap in my mouth once, wouldn't recommend it), this isn't immediately helpful to those of us whom do not already have an Oculus Rift. Plus even the DK's go for over $1000 (here in Canada anyway).
I wanted Orion with VR now, which is why I've been working on an implementation using Google Cardboard (plus a smartphone of course)! It only cost me $100 to build (including the Leap, which was $80 on its own). No expensive Oculus Required! This is great for developers who want to build VR (and Orion) desktop apps withought the need for expensive testing hardware.
The following repository is a full implementation of head tracking using TrinusVR + OpenTrack Redirect, and Leap Orion for hand tracking.
The devices gyro data is sent over UDP (OpenTrack redirect to port 5556 using Trinus). The UDP listener (embedded in Unity) picks up these packets and transforms the camera appropriately. Hand tracking is handled by the Orion implementation of course.
Unfortunately this will not allow you to play existing excutables that use Orion, however if the application is Open Source, it's very easy to implement my solution. Just drop the receiver scripts onto the camera and voila!
Detailed setup instructions are available on the GitHub page!