Savage Leather Farming in Twilight Highlands
The best place for you to farm Savage Leather in Cataclysm is in northern Twilight Highlands. There is a small field between The Black Breach and Dragonmaw Port where you will find four different kinds of animals for you to kill. Each of them are pretty squishy and when you skin them will drop Savage Leather. Another added bonus to this farming location is not many people even know it exsists which means generally you should expect to have the whole place to yourself. The only time you will usually see someone here is if they're flying by to pick a herb that spawns in the area.
In addition to getting leather and vendor trash here the mobs will also drop Toughened Flesh. Toughened Flesh may sell on the AH on your server depending on how many people are leveling Cooking. Another thing to note about this area is to ignore the Doe's that spawn by the elks. The does not only annoyingly run away from you after you hit them but they also do not drop any loot nor can they be skinned. As seen in the video below when I kill one of them to demonstrate.
Savage Leather Farming Video