In the latest 2.79 daily build, is it possible to convert the Bevel node's RGB normal maps to BW edge highlighters? On the left is the normal map generated by the Bevel node. On the right is an unbeveled cube with the Bevel node in action. I wish to convert this to a BW map where The edges/gradients are highlighted and the rest isn't. Does anyone know if this can be achieved with more nodes?
Final result and node setup:



After many tryouts with complicated setups it seems that this effect could be easily achieved by using Vector Math > Cross Product from Bevel > Normal output and Texture Coordinates > Normals. 

After this the most efficient way is to use Color Ramp to change softness/sharpness of the edges.