The "designer" boas are still the same subspecies being bred to eachother, with the unfortunate exception of some of the BCC x BCI albino projects out there
Where as a lot of the colubrid morphs are not same subspecies. Such as Albino Pueblan Milksnakes, they have been outcrossed with Nelson's milks. Creamsicle Corns are hybrids as well. Emoryi x Gutatta I think? Several of the corn morphs are called "corns" but have used an outcrossing to yield that morph.