I now have this finished.
I puttied and built up the base, embedded some small rocks and stones from my yard. Then Vallejo Coarse Pumice was brushed over the groundwork to tie everythin’ together. It was then basecoated in Vallejo Green Ochre, then drybrushed, and finally it was dusted down with some Mig pigments Beach Sand.
This is how I scratchbuilt the Persian shield, here: http://www.planetfigure.com/forums/showthread.php?t=23883