netherweave bracers = 18 cloth = 6g on auction
2 arcane dust = 4 g on auction -
Prices ma differ on your realm, of course, but more likely than not, the best way to convert cloth to enchanting materials is to auction the cloth and buy the mats.
I just shop for anything greater than 65 and 5-6g or less (depending on prices). Sometimes it ends up being something someone else crafted but usually not. I don't think there are really any patterns where you can buy the mats, create, and disenchant for a profit. There are, however, some that you will lose a lot less money on when trying to level up tailoring like arcanoweave boots instead of imbued netherweave once you get into the highest levels.