There is an island in azshara that allows instant respawn once you release(much like releasing in netherwing ledge or the netherstorm instances) except you can farm them right at the spawn point. So if you have another character on the opposing faction you can farm endlessly at the spot or even trade kills(you spawn at 50% each time easily two shottable at this level of content). Managed to get 1000 kills today with this trick(also no bones are left once a character dies)
Location
How to get up (get to the circle run into it and it shoots you forward, after that follow them till you get to the top)
Respawn spot