Ok, well if you want to make barred EEs "from scratch" just for fun, I'd use either a California Gray or a Legbar. Use a male over your ameraucana hens and look for a cockerel with small comb/wattles and a single copy of the beard/muff gene in the offspring. Breed that back to black ameraucana and repeat this process ad nauseam.
If you use the legbar, you won't have to deal with lurking white egg genes but will have to combat gold leakage. If you use the cal gray, that white egg situation can be a PITA. We're still battling it in some lines of opal legbars after who knows how many generations removed from Isabella leghorn.
Choose your poison!
And If you crack the leg color issue, let us know!