It's your lucky day. I know exactly where to go for one. Right outside the zantanna/etrigon instance. I have leveled up 3 characters to 30, and each one of them I got a snake style cape from farming the mobs in the parking lots, right outside the instance. Good luck.
Fiero Drago Lvl 30 Fire Brawler No Man's Land Doctor Death Lvl 30 Nature Rifle No Man's Land