^ The trouble with converting it to black and white is that usually you'll need to increase the contrast. Otherwise it becomes on giant gray blob. For instance, the brittest color you have now is this one. Original is still better.
I like the concept. Only issues would be the somewhat overexposed stock (not very, but it's noticeable) with its lack of integration and the simpleness of the type. Blend the stock a little more; it's practically its own element (and the overexpose doesn't help that), and doesn't go too well with the whole sig as a result. As for the type, it works, but I'd try and integrate it in with the little spheres you've created to add depth in the centerleft of the piece. The whole thing has more of a 3D feel so I think it'd help if applied to the type.