- Bring a bunch of Stormchops with you.
- Go to desired area (Example: Fray Island in Northern Barrens for Steamwheedle Cartel rep) on both characters.
- The Stormchops give you a 30 minute buff that will give a chance to inflict lightning AoE damage. Unequip Weapons/Armor and start up a partied duel with your friend/alt within range of a dense group of mobs and both of you eat some stormchops. Your enemies will take damage as you're both pummeling each other. Works best with classes with a passive HoT (just in case) and 2 PvP trinks giving you the 15% damage reduction set bonus.
You'll have to refresh the Stormchops buff every half hour, but I do not think there is a maximum duel time.
Ideas and other conclusions:
If you use a Thunderfury you might be able to reduce the nature damage in an aoe. Potions don't seem to boost the nature damage of the lightning. With 2 hunters+pets you should be able to spread out and kill in 2 areas of the map.
Please do feel free to add any additional ideas/info below and I'll be sure to rep up and credit you in the original post for your finds