There are a few breeders with impeccable reputation.
Deborah, one of our Moderators, has BEAUTIES for sale, and her husbandry is perfect. Dynasty Reptiles has all their buyers happy from what I can see. Justin K., Ozzy and a few more are also trustworthy with amazing animals.
You could simply get 3 BP from the same breeder/facility and at the same time. Why not, since you are planning so far ahead. Then you can set them up in your rack right away, since you don't need to quarantine them from one another.
I would buy supplies, enclosures and whatnot at shows. Never an animal. But that's just me.
I know many of the good breeders DO go to shows, so there is the chance of them bringing something home to their own collection. But I think they have procedures in place to prevent that. They have to much to loose, to allow a stray mite to get back into their collection or to let people handle their snakes without some precautions.
Just an idea..