hehehe - yes, I love those rich warm tones a lot too!
“Cheese” is from a macro photograph of cream cheese under bulb-light so it became very yellowish and “Mango” is in fact from a gallia-melon (?) but it looked as rich yellow-red as a ripe mango to me 
At first I only did the MatCap thing by the book, starting with my white-porcelain teapot standing at the window, but soon after that I became more experimental and simply picked the tones I wanted to see from the different directions.
With the sphere preview while picking and rotating the markers, you can really “model” your surface. (Although it is broken if you zoom in or out of your document)
BTW: This is one of the photographs I used (for “Green Clay”), pastel chalks from a local art shop… :
I just have to fully understand the two-material process now…
I think MatCap is the work of a genius, giving everybody the power to create or match materials without caring for all the technical crap. Just take your digicam and go create…
While I personally have no problem with the technical part - having written quite a lot of shaders in C myself for messiah and Mental Ray - I know that many people have a hard time with it. And Zbrush once again shows that this doesn’t have to be complicated at all…
I could even imagine driving this quite a bit further actually with an “advanced mode”…
Complex IOR stuff comes to mind - in the end, it is nothing too different…
And those cavity maps are something I would want to have in every other software too… hmmm… Should be quite simple to code actually… 
Well, with MatCap available, I am sure the amount of available materials will rise very fast.
Cheers!
Thomas Helzle
