Paint layers in cycles?

I was trying to do a node setup in cycles where I could paint in layers similar to mudbox. This included several image texture nodes and then colour mix nodes to include an opacity channel to them, then I was trying to mix them. I think I’m on the right track but the results aren’t close to what I’ve watched mudbox do. Am I mistaken thinking I can do a setup like this?
For those of you that haven’t played around, if you texture paint with the material setting, it shows all textures, if you have the node editor open you can easily select the image you want to paint. Really, I think it’s just determining the proper node setup and whether it’s set to overlay, mix, etc… Has anyone done this before?

Here is one of the many versions I have given up on. Thoughts? Ideas?