Yeah, Liesens are the new "it" line in black pastels. I haven't seen a Liesen super yet, though...
Mine are Ian G. line, and I got them from Dynasty Reptiles. He usually has some nice ones, and I like the way his supers turn out.
Heather's Herps also works with them, but I don't see any for sale this year. (Except for the female bullet, who's apparently half cinny/half black pastel.)
...most people won't mislabel a cinny as a black pastel. Cinnamons are generally cheaper, but a lot of people prefer the cinnamon pewter, so they still have their own market pull. If you have any doubt, though, check the breeder on the Fauna BOI and go with a well-known, well-reputed breeder. And look at the snake--you basically get what you see with black pastels and cinnamons.