I gave Silk Cloth farming a go with a level 35 toon and made about 3300g in 60+ minutes. Not only did that contain Silk, but also Wool and the occasional green and rare item. Greens of this level DE into Soul Dust usually, which I've sold for even 150g a stack when supply is low. I've sold Silk Cloth for 40-60g usually and it sells always! Rares have a price tag of 100-200g but sell very slowly.
A hour spent farming should cover all your powerleveling costs until level 85, or if you want to grab epic flying training aswell when the level is right, spend 2 hours farming here instead! :)
Protip: List all cloth in stacks of 20! Most players ignore stacks of 1.
Where to farm?
Slitherblade Naga (Desolace | See map)
Scarlet Monastery: Cathedral (Instance)
Personally I prefer the Naga farming in Desolace because they spawn so fast you don't even have time to loot them before more spawns. They also drop raw fish that cooks are often looking for. Instances have the 5 per hour limit so it will slow your farming.
If you want to farm more cloth, click on "Farming" and look for more! There's a whole post with secret, instant respawn cloth farming spots if you missed it previously.