Definitely get your Dwarfs or Super Dwarfs from a credible breeder who can tell you the genetics, otherwise you run the chance of your "Dwarf Retic" being a "surprise 20ft Retic".
Like others have said, reptileexperts is the guy I would go to about Retics on this site. He should be able to point you in the right direction for what you want. Also remember that Reticulated Pythons are on the Lacey Act, so in order to obtain one legally you have to purchase one within your state, which might limit your choices.