Are there any well-curated directories of Bitcoin mining hardware manufacturers?
The current king of the hill is BitMain and their AntMiner S9. They provide 14 Th/s, but it's sold out at the moment.
Unfortunately, the industry changes so fast that it's hard to have anything current. Companies go bankrupt, new manufacturers appear out of nowhere and it's hard to keep up. The best directory of manufacturers and their wares is here: