Okay so this isn't revolutionary or anything but I thought I'd share.
There is a mob that is used for a horde quest that is attackable by alliance players. His name is Grark Lorkrub (Grark Lorkrub - NPC - World of Warcraft) and he is located around all the Orcs at this area inside of a fortress type thing. Basically, you can just sit there and hit him and at 25% he will "surrender", instantly going back to full health. You can do this afk if you want but watch out for Horde questers. This is obviously more for higher leveled players.
I'm doing this right now and I'm about to hit 400 maces... So I figured I should share. I did a search and didn't see anything so, enjoy.