The E-M1X has a large body not just because of the intetegrated vertical grip, which holds two batteries, but to accommodate the dual TruePic VIII image processors that deliver the power necessary for several of the new capabilities.
As is typical for Olympus, the OK button pulls up the options for the main shooting controls. The texture on the navigation buttons and joysticks make them easy to feel and use when your hands are cold.
Given that with the integrated teleconverter this lens has an effective total focal length of between 300mm and 1,000mm, it's pretty small. Those black spots are buttons; there are four so they can be used no matter the orientation of the camera. Olympus doesn't yet have pricing or availability info for it.