Try Riftseeker's Sanctum for this slayer quest "Planes, Trains and Element-iles". I liked it because of the wide open spaces. You can run around the whole zone while everything aggro's in about 20 minutes, and you don't get stuck or have to run around a big table or something like that in every room. By the time your done a run, everything has respawned. Seems the King and Queen pop every 24 hours. Just take's time for 10,000.
Happy Hunting!
- Diva Rogue Forever