SLOF MAN is a producer from South West London, he been producing for about two years, and is now getting onto the DJ scene as well. He has a free album available on his blog: http://slofmans.blogspot.com/
HD4000 is actually two people: Odeed and Wish. After producing breaks together under various aliases since 2003, they discovered dubstep one evening in San Francisco - playing breaks at a underground party for a close friend of theirs. Odeed and Wish were the only act that night that wasn't playing dubstep, and after their set, they stayed to hear what it was all about.