You are also making an assumption with a multicolored fish (in the wild) that there is a pattern of dominant colors. That is a great question. I wonder though if the answer to your question is "not really".

This is why careful guppy breeders are very picky about which fish they select to breed. They know that otherwise, incomplete dominance will give people who just mix anything diluted and inferior strains.

Also Google Guppylog for Stan Shubal (who just had a second book on Guppies come out on TFH Press by the way), Iwasaki and his book on guppy genetics and Angelee. They either have been mentioned in terms of breeding for colors or in the case of Angelee have held forth on the topic here.

A lot of times we don't get what we want in a search because we just ask one question. Vary how you phrase your queries and you will find more. :)