So a few months ago I decided to order a Ghost Mantis from FunSizedZoo.com. I had heard good things from them but I decided to try it out myself.
I ordered an L5 Ghost Mantis for a relatively cheap price, one that I was happy with. After I ordered, I decided to email the website with my order number and see if they had any Ghosts with black coloration. The man who replied was very nice, he told me that it was difficult to tell what color a Ghost would be until L6-L7. However, he told me that he would gladly take his best guess and get me the darkest colored Ghost he could find.
A few days later he sent out an email that there had been an accident at his apartment with water pipes and that he was not able to ship out orders the day he had promised. I said this was fine, accidents happen. After just less than a week, my Ghost came and it was active and healthy! He told me that he had forgotten to check which gender my mantis was and said that I was welcome to send a photo. I did, and he informed me that I had a female Ghost mantis.
Funsizedzoo.com had excellent customer service and gave me a healthy, live mantis (even going out of their way to find me a specific color). I would recommend them to anyone looking to buy a mantis in the US.