The biggest problem with this theory is that the vast majority of juveniles sold will never make it to breeding size/age. Look at albino boas/pythons/etc. Many times traits based on simple recessive gene mutations stay in high demand because they are harder to produce, especially compared to co-dominant and other traits. The interesting part about tortoises is that they take a long time to reproduce, thats why you don't see many morphs.

-----
bigdnutz
1.2 Suriname Boa
1.0 Venezuelan Boa