snyder17315 said:
Nothing. The one with the 70-200 attached is a 60D with an articulated screen.
Indeed? Evidently you're seeing several things that aren't there... First off, there's no 70-200 in the pic, the white lens is a 100-400mm. Second, the camera attached to the white lens has a multicontroller (aka joystick), which the 60D does not, and also lacks a popup flash.
I still don't know what the accessory is, but I wanted to correct obvious mistakes...