Version 1 - Layered shader tutorial using the Maya 2015 MILA material. There is a lot more to show / say on doing some advanced layered workflows...but this is a start...
Mia Maya Help Doc: http://download.autodesk.com/us/maya/...
Recommended Mental Ray Shader doc:
http://help.autodesk.com/view/MAYAUL/...
MILA Mental Ray Blog Post: http://blog.mentalray.com/2014/04/18/...
RGB Texture Mask Workflow video: • Maya RGB Texure Mask Workflow