I might as well go for broke and shoot for the moon:
A local hatchery that could, and would, accurately sex their fish and gladly sell me all male BG, and all female YP.
Bonus points if the above-mentioned hatchery would successfully feed train RES, and could readily grow them out to a larger size.
And in the all fantasy realm, a Blue Tilapia subspecies that could over winter in my ponds.