It's an interesting discussion and the sample image that's posted is also interesting.

For fun, I thought I'd do my own Carrara version to see what I could come up with.

If you look closely at the Carrara image over in the Carraracafe thread, the lighting uses buffered soft shadows and has several light sources employed.  From the way it looks, it doesn't employ GI at all.

The image I'm posting here has two lights (which I believe is more similar to the Luxrender.

Kinda interesing stuff.  One thing I'd like to know is what the render times for the Luxrender are like.

-Kix