Found this:
The area is in Azshara, I play Horde Hunter and only ever saw one Alliance in the 4 levels I was there. The flight path takes you to Valormak, the area I grinded was just South West of here. If you looked at it from the top it looks like a huge bowl. In that area are beasts ranging from 45 - 48 which for a Hunter are really easy to kill, also as a skinner I made 400+ Rugged leather and about 4g in gold without auctions.
The mobs are - Thunderhead Hypogryphs and Mosshoof Runners. They die pretty quick and I never died once from them, you have to watch out for the Level 53 Elite Giant that wanders the area though as he can sneak up on you when your not looking. There is a meat vendor and weaponsmith nearby (food for you and pet and repair items/ sell junk) Also with it being so close to the flight path you can get to Orgrimmar quite quickly.
I did from 46 to 50 here in 3 days ( about 36 hours playtime ) bout 9 hours or so per level so its a good area to power level. It may not be the best or anything but it worked a treat for me... Just wanted to share the area with everyone as I found it useful.