Things were different 5-10 years ago. There were several 're-mailers' who would import bulk powder into the US, mark it up, and sell it. It was easy to find. The problem is that there is very little profit margin, and the risk is high. It's more profitable to make your own gear and sell that. Profit margin on reselling powder was like 50-100%. Profit on brewing and selling your own is probably 500-1000%, and probably 2000% if you sell it locally.
Now you have to go directly to china pretty much. Just call some chemical places in China, you'll easily find someone who makes them.