I actually breed super dwarf and dwarf retics. This is my first year breeding (one pair) and will be my first clutch of eggs if I'm lucky. I'm breeding a white albino with a purple albino, so all babies will be lavender albinos. They will be a mix of super dwarf and dwarf with a little mainland in the mix (all super dwarf and dwarf will have mainland if they have a morph other than Normal). I'll be sure to post photos if I get eggs and let everyone know how it goes. Eventually I'd like to get other morphs but really don't want to start with Mainlands, I'll have to hunt down some SD crosses. One of my snakes is actually 100% het Anthrax so the babies will be 50% het.
As far as I know the only state that bans retics is Florida. I don't think there are any other restrictions in place. The Lacy act used to ban interstate transport of retics but that was defeated, now you can ship across state lines (thank goodness!).
I know a lot of people stress the percentage of super dwarf in the snake but I think the size really depends on the percentage of mainland. My super dwarf is only 12.5% mainland and my dwarf is 50% mainland. There's a big difference in size! My babies will be somewhere in the middle, they should grow to be about the size of a boa.