Best places to farm boxes for high levels?

Or Oblivion 4/5 if you don't care about the familiars, just want the most kills per minute.

That is what I do, the flat map with the three platforms is pretty fast as you can just go back and forth and is pretty good for all classes (even buccs with their crappy mobility). If you can, bring a Kanna mule to increase spawn (this is easier in ToT since their is not a level/tele restriction).