I am a leatherworker and I can make the Clefthoof set, Netherfury set, Felstalker set, and the Fel Leather set. All of them have a set bonus and I believe all of them also require 350 LW to get the bonus. This is why the sets rarely ever sell on AH (I ended up having what I had made DEed). Well, that and less than 2% of our population on my server consists of tanking druids or shamans.
I made the Fel Leather gloves for myself (I'm a rogue), and I've been making the Felstalker set for all the hunters in my guild, but the Netherfury and Clefthoof sets seem to have not been worth the gold for the patterns. This is probably due to the fact that the people who actually want the sets bad enough are probably leatherworkers and can make them themselves.