I seen them in liveaquaria diver's den from time to time, but they sell the shrimp paired with gobie and they sell those pairs for a lot of money. I see marineCenter also has them.
I have one, it is very tiny, and I don't think they get to any decent size either. I have amphi pods in my sump bigger than that shrimp. It would work for a 10 gal nano.