Like I mentioned earlier, I have been testing out some VrayFastSSS for making marble. This is my result, and I think it looks awesome. One image here is the rgb channel, and the other is the SSS. I also used a shellac on top of the VrayFastSSS, in order to also make the marble reflective. You can see from the SSS channel that there is some nice scattering of light going on, especially in the bird's beak. Of course, for marble, the scattering is very subtle. I uploaded the .mat file for this marble, and also put all my maps in there. There is a marble diffuse, normal bump, reflection, and reflection glossiness. Feel free to try it out, the link is HERE.
Also, if you make something cool with this, go ahead and add it to our gallery. I would love to see what you can do.