Nice animal, I have some of that same line myself and they are one of the my favorite Sotuherns. As far as being a true leucistic like a tx. rat is concerned ,it is somewhat interesting. The word leucistic as you know is defined as a solid white snake with black eyes which these definitely are. As far as being leucistic and far as the leucistic trait being a simple recessive trait they are not. Mark produced them by color breeding them from a number of combination of the patternless gene and several others and then increasing the amount of white over a number of generations by selctive breeding as you probally know.
In any case they are indeed some really awesome animals that are a lot of fun to work with. This last year out of two completely white animals I got a clutch of 11 eggs. Two were patternless and a solid light tan, 3 were soilid white as yours is and the rest were the white with a tinge of very very light pink around the neck area. Kind of like opening christmas presents when you have a clutch hatch. You ought to see the results of an albino breed into this line, they are awesome also.
Someone ask thrugh an email why the price on them is so high. Simply said the price of those solid white ones are really high because of the work that goes into producing them and the rarity in the hobby at this time. As more are produced I would imagine the price will go down as it does for any other morph. But that will not be for a few years anyway.
Take Care and good luck with them this year.
John Cherry
Cherryville Farms