Imbued Netherweave Bag

Each of these bags requires the following materials:

60 Netherweave Cloth (requires 4 Bolts of Imbued Netherweave, each of which requires 3 Netherweave Bolts, each of which requires 6 Netherweave Cloth)
2 Netherweb Spider Silk
8 Arcane Dust
1 Greater Planar Essence (or 3 Lesser)

Still, with the rate at which Netherweave Cloth drops in instances like Hellfire Ramparts, Blood Furnace, or the like, 72 per bag is not an unreasonable requirement.

The cost of Netherweave Bolt went down from 6 to 5 Netherweave. Therefore, you only need 60 Netherweave for 1 bag. 60 Netherweave Cloth (requires 4 Bolts of Imbued Netherweave, each of which requires 3 Netherweave Bolts, each of which requires 5 Netherweave Cloth) 2 Netherweb Spider Silk 8 Arcane Dust 1 Greater Planar Essence (or 3 Lesser)

In addition to the above: A tailor/enchanter can get the 8 arcane dust via http://www.wowhead.com/?spell=26764 Netherweave Bracers. You need 3 bolt of netherweave (18 netherweave cloth) and a rune thread to get on average 2.5 Arcane Dust. For 36-54 more cloth plus a handful of silver, you can get the dust cheap and make a tailor/enchanter happy. The greater planar essence comes from disenchanting lvl 102-120 green weapons. Someone may be able to craft this cheaply to be disenchanted. See http://www.wowhead.com/?item=22446#zccRz for a list of weapons it can come from. A lvl 325+ blacksmith wil