I'm no expert, but I think ya'll are making this more expensive and difficult than it is. Color shifts are just a combination or more specifically layers of paint. Take a taxidermist for instance, he can recreate the perfect colorshift replica of a true fish and never spend more than $6 for a 4oz jar of paint. I'm not talented enough to shoot an expensive large pearl auto paint that requires a .10 mm needle on a 2" bait. Plus ya still need to layer the right paint/base underneath or the color shift wont show.
Its all about the layering of paint, not a magic color in my opinion. Save yourself some $$ and buy the highlite stuff from Wasco like someone else mentioned. Top it off with some transparent colors and you can create any color shift you wish.