There was a thread on it just a little while ago, look back a couple pages. JimsFarmStand started it. I believe a professor at a university started the project? He used true Araucanas and commercial (not hatchery) strain Leghorns.
It is, but not by titanium chains or anything Legbars themselves have single combs and lay blue eggs, plus there's a strain of Dorking in the UK who lay blue eggs, and then there's the recent development in the US of production-laying single combed blue egg layers, so, it is possible.
Umm, Cuckoo Easter Eggers, Cuckoo Araucanas, and Crele Penedesencas too All those can create Olive Eggers sexable at hatch and the egg color will still be just as good.