I did a little research on this topic. It looks like the red-to-orange-to-yellow aspect of pod color determination has three genetic loci segregating, giving fruits ranging from white to lemon-yellow to orange-yellow to red. The differences here seem to be different amounts of synthesis of capsxanthin and capsorubin--yellow and red pigments respectively. Looking at 2god's chiles, I'd guess they have a basic color that's yellow with a blush from erythrocyanin--the blue-purple pigment in red cabbage that's there in practically all plant material. Maybe you could start by finding a pure line of light lemon-yellow C. annuum (maybe mjdiamond's cayennes if you can't find something more pale) and then finding a way to breed in some up-regulation of erythrocyanin production from a purple-foliage C.annuum.
Anyways, here's the paper that is most often cited: Hurtado-Hernandez and Smith 1985. Inheritance of mature fruit color in Capsicum annuum. Journal of Heredity 76,