Yep, this is something that I’ve hoping would come out for a long time. It be useful to have separate layers for highlights, shadows, specular, depth, color, reflection, cavity transition…
A layer that makes the background black and the model white for masking in PS would be useful.
I guess that you could do a lot of that if you could compile multi-layers per materials in a single PSD.
A plug-in that would allow up to 10 layers of the attributes of your choosing would be awesome. One that would let you choose what you want and how big/small you want the file to be (layer wise).
I’m thinking that resolution would have to depend on your document settings in Z-Brush at the time.
You can up-scale quite a bit further in PS, depending on the resolution of the image.
Just some thoughts.