I am still a few hours from 72 so I've yet to try it myself, but the logic seems solid and thought it would work good for boxers. This is not my idea and I take no credit for it as I saw it on another forum earlier today:

7k Per kill at level 71 Easy kill
In the quest Mighty Magnataur you have to kill 3 Magnataurs which are fairly easy. They also give 7k xp per kill and spawn ever 10-30 seconds. So heres how you do it.

For casters-
Iceshatter is the best choice for a mage to kill, since he casts and wont be hitting you.
Strategy-Just kite around with any instance cast spells when he starts casting move 10yds away and nuke, easy kill

For melee-
Drakegore-He is the best choice for melee to kill, since he doesn't cast any spells or anything.
Strategy-Just a mixture of kiting and straight up attacking

Heres the quest for you people who want to know where to go www.wowhead.com/?quest=12149