I just went through their lists of offerings for 2018 and didn't see any dwarf root stock trees.
You can simply Bonsai a full sized tree though and that will give you a small tree with their great fruit.
Plus the tree will live longer than a dwarf root stock tree.
We love visitors, that's why we live in a secluded cabin deep in the woods. "Buzzard's Roost (Asnikiye Heca) Farm." Promoting permaculture to save our planet. you can call me Dr. Redhawk