This model was painted by Kevin K. a fellow Tau enthusiast. The model was done first with a top-down highlight with an airbrush. Basically how this works is you cover the entire model in your shade color, and then spray from the top down with the main highlight color. I think in this case the original shade color and the highlight were too similar to get any contrast, so the painter went back with the airbrush and sprayed in the shade color in certain spots.
The painter used Paulson bits from this site: www.paulsongames.com.
The head and twin-linked fusion blasters on the left arm were all built from Paulson's model parts.
The base isn't done yet, but you get the idea.