That’s a nice setup, but it still kind of looks like a rubber suit. I don’t think there’s anyway to avoid this unless you could paint the “thickness” on the skin. That is, change a parameter on the vertex level that affects the stretchiness and friction of the skin, making it seem thin in places (deformed a lot by the muscles) and thicker in others (hardly stretches at all).
Maybe if you changed cloth properties on the individual panels you could do this. What would really be nice though, was a system that dynamically did this to the areas of the skin that were stretched.

:buttrock: 