I used to breed and sell bettas in the '50s and '60s and am now trying to help my grandsons do so also, but I am disappointed at the poor color purity and fin patterns in the fish generally available. I used to have a booklet on betta genetics, primarily colors, by I believe a Gordon Myers. Does anyone know of this book and if it is still available?
Where are you looking for betta color references?
Obviously you would know more than me about breeding, but if you haven't already, you might want to check out aquabid.
The 5 guys in my signature are all pet store bettas, but 3 of them are not your typical LPS find. Pet stores tend to get duller and less attractive bettas. Probably because actually experienced betta breeders sell them individually on places like aquabid. I always got the feeling pet store bettas came from more inexperienced, uncaring breeders that are just looking to make a quicker buck? But that's just the impression I get :)
If you want to get back into breeding you're going to want to hunt aquabid or similar websites until you find bettas of the color and quality you want. I know there are several variations in color an patterns that weren't around in the 50s and 60s, like the newer dragon scale bettas.
If you are lucky your local pet stores might carry nicer looking bettas, but 5 out of the 6 places I can get bettas locally almost never have anything interesting or particularly nice. The other one also never really carries anything show quality.