here is the deal. if what you want is a true red tail, it doesn't matter. either way you will be getting a Boa c. Constrictor versus a Boa c. Imperator (common boa, not a true red tail). you see, snakes don't honor borders. the truth is, there are no physiological characteristics that seperate guyanans and surinames...peruvians. they are all the same sub species, and they can all interbreed and cross borders. so if you buy a suriname, it's parentage could be brazil. or columbia. infact, unless you pick your animal out of a tree yourself in the country you want it to originate from you just don't know. the "locality" trade names are usually just sexy industry speech. if your looking for a breeding product that will yield a hot return, look at "peruvians," they seem to be sought after right now. but if you just want a great looking red tail, find a reputable breeder and cherry pick yourself a beauty. oh, and boa c. constrictors can exceed 12 feet, but usually not by accident. 8-9 is more common. good luck finding your animal...post pictures when you do.
best wishes, chris olson