Mike Bodner breeds ones of the best thayeri i've ever seen thayeri kingsnakes - Captive Bred Thayeri Kingsnakes not exactly sure where he is from, but he has 100% thayeri only.
the other guy who produces insane snakes Highland Herps - Home my babies are from him. He is great to communicate too.

The other one i've heard a lot of good things is from Alaska, dont have his info on hand.

Just think about kings in comparison to others: they dont eat much, they don't grow big and dont need big cages.......