Good article citing a PPG study on car colors that Americans buy - silver comes out ahead at around 25% of all cars. Specialty Colors (guess yellow is in there, since not mentioned elsewhere) at 3%. New things coming up: liquid looking paints, sparkling paints, and more. Says something about broadening the palette in the future - more colors?
When does paint spray technology get to where we can choose from an array of colors, designs, accents, etc. from a large book of choices and get it straight through the dealer at reasonable prices? Cars are a major personal expression - bet it heads that way. Dealers already have more wheels, etc. than before. People like to customize their rides.
Side note - I think Porsche was in early on custom colors, but very pricey.
http://www.cnn.com/2005/AUTOS/10/27/car_colors/index.html