It seems the devs took notice of the fact that many important wow tanking enchants were just plain missing from Wrath, because we're getting a couple of new ones in patch 3.0.8. At the price of 5 Abyss Crystals each, you can buy the following formulae from the Shard Trader in Dalaran:

Enchant Bracer - Major Stamina: Teaches you how to permanently enchant bracers to increase Stamina by 40. Requires a level 60 or higher item.

Enchant Weapon - Titanguard: Teaches you how to permanently enchant a melee weapon to increase Stamina by 75. Requires a level 60 or higher item.
 
Before Titanguard, Mongoose remained the best wow tanking enchant (unless stacking threat stats), which was just downright silly. It's still a good avoidance enchantment, but for your pure tanking set you can't really pass up +750 HP on your weapon, before any talents or buffs are thrown into the equation. That's pretty incredible!
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