Anaheim, eh? You might want to drop by SIGGRAPH in a couple weeks. You can get a free exhibits pass from Pixologic ZBrush here: Pixologic :: ZBrush :: Pixologic at Siggraph 2013
I don't know where exactly you should look to find level designers, but the Pixologic booth is probably a good place to hang around. A lot of environment modelers use ZBrush, and there's certainly some overlap in those disciplines.
I don't personally know any LD's at the moment, as I have limited contact with games industry folks.