Farming cloth still exists! It's possible to farm cloth at any level of cloth! Most server's have cloth inflated so much right now. Here's the prices that I'm seeing throughout my 9 servers. These prices are all per stack of 20:
With the prices so high on Linen cloth you would be crazy to not want to farm these. Obviously Netherweave will be the highest priced cloth, because it's the hardest to obtain. If you are a level 70 you may want to read this and find out which spot would be best for you. Some of the other grinding spots may be better for different classes.
With that being said, the price of Linen and Wool is so low on most servers that it's not good for high levels to farm. If you are a lower level there are some great places to farm these and get some early cash rolling in. So for the sake of every level I will list each place to farm.
The best type of cloth - linen cloth
Linen cloth is by far the easiest to farm. I have a great spot that has been "bugged" for such a long time and blizzard has YET to fix it! You are going to need to be a little higher level if you are horde because it's found in a Alliance Zone. If you are on a PvE server then you don't need to worry about this.
The place is "The Defias Windmill" you can find it in Westfall. It's a great farming spot because the mobs re-spawn almost immediately. You can find these Defias Windmill near the Gold Coast in Westfall. If you follow the mountain ridge you will see a big Windmill when you get closer to the Gold Coast. You will also see level 12-13 Defias mobs around the Windmill (There's about 6-7). Great place to farm, great place to level new weapons. Also keep in mind with dropping mobs this quickly, you will be able getting a flood of greens and vendor trash.
If you followed my Auction House guide, you will know that you can take those green's and put them on the auction house for a nice price instead of vendoring them for 5-10 silver. You can easily make 75g/hour if you really know how to use this place.