I've been leveling my Draenei Shaman recently and found this great spot in Duskwood. The mobs are all lv 29-31 and respawn insanely fast. Plus they drop money, the occasional green / blue and are skinnable! Here's a video showing how to get there and showing the respawn rate.
I've been grinding here for a level and a half and have made about 10g from just looting, 50g or so from skinning and got a nice pair of gloves (Thorbia's Gauntlets) to use on my Paladin twink (once I get my Shaman leveled up of course :P).
Notes:
There are two Tin Veins that spawn in the area that you can grab if you are a miner (65+ for those who don't know (seriously some people might not!)).
All the mobs are melee, so higher armor helps.
The mobs have a disease and a poison that they can cast, if you can cleanse them it will help.
You can stay on top of the cliff if you have trouble at the spot on the ground as a caster, however you won't be able to kill all of the mobs in the area (line of sight / range issues) and they will respawn slower.
Addons for those interested:
Carbonite Quest
Atlasloot Enhanced
Dominos Action Bars
Cooldown Buttons
Mik's Scrolling Battle Text
Tbag
Perl Classic Unit Frames
Pmap
Pminimap
SellFish
by vampllama