Material rendering black By that I mean things with a specific shader are rendering black, though the shader will render if I disconnect everything except ye olde diffuse, glossy, and mix shaders

For brevity, here's the blend.

Today, I rendered again just to reaffirm the problem, but the model did render for some reason. At this point the shader was the exact one in the blend file I linked. Again, still an exceedingly simple shader at this point.

But when I attempt to plug something into the material output's displacement (I wanted to try the same texture data used in the mix shader's fac input, if it matters), the model renders black again. 


The shader's preview in the outliner panel shows up properly
Not sure exactly what you are asking. 

I took a look at your blend file and the only thing missing was a light. I just added a sun lamp and everything seemed fine. I noticed you had some emission shaders on some layers and not on others. Also the emission shader you did have was very far away and not pointed in the correct direction. It was lighting up nothing. 




Hope that helps.