With great input and help from Rawalanche, I'm finally starting to like the "carpaint" shader we came up with.
But, I've noticed Corona getting a bit slower and slower with newer releases.
I understand there has been a significant improvement in quality to the DOF and MBlur particularly, but the rendertime here (1 hour) still shows some noise and jaggies.
It was rendered with the assert version, though, but still, this rendertime is a bit high to Corona standards. :)