Well, for all humanoids, cloth drops are based off level. If you need silk, you will just have to kill higher level stuff. I think you need ~25+ humanoids for silk.
This is blizzard's way of restricting your tradeskill level by your class level. It only gets worse.
Basically, you're gonna have to wait.
As a priest i don't do much grinding, so i do instances like stockades and gnomeragon, then my party lets me have the silk. I also have a few people in my guild that keep my inbox filled with cloth. A great way for me is to partner with my mage friend while we AoE humanoid camps. I heal him while he nukes, usually kill 10 evens in 20 seconds. End up with good xp and 3 or 4 stacks of cloth.
Basically, with tailoring, you are always needing a cloth you can not farm yet, for an item you can not wear yet. Once you get high enough to wear it, you no longer need it.
So be patient and don't buy it off the AH.
Edited, Thu Jan 6 17:14:26 2005 by slgray