Sure, Brown Red is one that is gold based, and Buff is another, and so are wheatens and blue wheatens. But when you start crossing varieties other than the wheaten varieties you are back to easter eggers. Ameraucana by definition is true breeding, not a sex link cross. My advice would be to sell them for what they are.
I get what you are saying, and technically any "project color" would be an EE if you choose to interpret it that way. Lavenders were also EE's for a long time, right? Is a splash bird considered an EE or just AOC? I haven't showed chickens since my 4-H days, so the differences are not that obvious to me.
If I got a strain of cuckoo Ams and used those pullets to create black sexlinks, would the pullets not be true Ams that could even be shown as blacks? Perhaps they would not show well against a good strain of blacks, but genetically they are black Ams, the cuckoo gene not being present at all in the pullets from that cross.
You might not see the utility in that, but if a family with 4-H age kids in suburbia (where roos are not allowed) were able to purchase known pullet chicks to keep as layers and also to show in 4-H, that seems like a win all around. Right now, I have no solution for them other than to raise a bunch of straight run birds and try to re-home the roos, which is painful for a family that has grown to love them all. Families like this now buy my Cream Legbars or Black Sexlinks (black Am over California Grey pullets), neither of which are showable in 4-H (or elsewhere). I believe that Ameraucanas are close to the perfect "first chickens" for 4-H'ers, and I'm planning to actively sell into that market here. Some people can have roos and some can't, I want to help both groups.