Around here, most breeders seem to be after a more even color but I can't find anything in the standards. Do you have a link to something I can reference?
There seem to be some differing opinions on Ameraucana egg color. Some do not consider green egg layers to be true descendants of the rumpless Chilean Araucana. But indeed, egg color is not considered in the U.S. for show birds.
http://www.heritagepoultry.org/learn/ameraucana.htm