Sources
Pristine Hide is a skinning hide, and can be found when skinning creatures in the new areas to be introduced in Cataclysm and can be bought for 10 [Heavy Savage Leather] from Leatherworking recipe vendors at every capital and in Twilight Highlands.
As an ingredient
[Assassin's Chestplate]
[Belt of Nefarious Whispers]
[Bladeshadow Leggings]
[Bladeshadow Wristguards]
[Bracers of Flowing Serenity]
[Bracers of the Hunter-Killer]
[Charscale Leg Armor]
[Chestguard of Nature's Fury]
[Clutches of Evil]
[Corded Viper Belt]
[Deathscale Leggings]
[Dragonfire Gloves]
[Dragonkiller Tunic]
[Dragonscale Leg Armor]
[Drakehide Leg Armor]
[Earthen Scale Sabatons]
[Ethereal Footfalls]
[Footwraps of Quenched Fire]
[Gloves of Unforgiving Flame]
[Heavenly Gloves of the Moon]
[Leggings of Nature's Champion]
[Lightning Lash]
[Rended Earth Leggings]
[Royal Scribe's Satchel]
[Stormleather Sash]
[Thundering Deathscale Wristguards]
[Treads of the Craft]
[Triple-Reinforced Mining Bag]
[Twilight Scale Chestguard]
[Vicious Fur Cloak]
[Vicious Hide Cloak]
Patch changes
Patch 6.0.2 (2014-10-14): Stacks to 200, up from 20.
Patch 4.0.3a (2010-11-23): Added.