I think people are hesitant on selling Sulawesi shrimp due to their sensitive nature. They have a reputation for not shipping well and their care requirements can be more difficult and therefore more expensive. They actually are not that hard to buy or even that expensive for most wholesalers. I know where to get some at wholesale but I am not touching them either.
You might want to try bobstropicalplants.com. He doesn't have any listed on his site but I am pretty sure he carried them in the past.