Here's a tailoring spreadsheet made for cataclysm. When you download the tailoring spreadsheet you will see a column on the right side highlighted in yellow. Update the prices of the items according to your server. The spreadsheet will automatically calculate if you could profit from crafting an item. Dreamcloths have a price even though it is a BOP because you could be selling your cooldown. Don't put 0 because the cooldown does have a price. Some people do buy other tailor's dreamcloth cooldowns. Also, instead of using the price of bolt of embersilk, I used the price of embersilk cloth in the equation. Making your own bolts is a lot cheaper than buying the bolts directly from the Auction House.