I asked Brian Sharp about this, he said that "Dwarf Retics" are really nothing more than a specific bloodline related to the smaller groups of retics that reside on some of the smaller island chains in their native range. Basically, these particular snakes have gotten smaller through the eons just because of a lower supply of food.

He mentioned that these individuals are relatively rare in the pet trade, as compared to the so called "dwarf" retics that you see for sale at shows everyday - basically, ill-informed people have treated the "dwarf" thing like a separate gene and crossed them with normal, non-dwarf retics. What you have now are the offspring of these crosses, so called "dwarfs", that still grow 10'+, and adding to the confusion on the whole thing.