The best web design company on the net is probably
http://www.sevenedge.be/ who have designed the websites of really big websites. But prepare to pay for what you get, they're extremely good, but also very expensive
Prices can go up to 10k euros for just the PSD, nothing sliced.
They do design adult websites on request, but they're excluded from the portofolio. An example is cams4pleasure.com