The camera has not built-in flash
-The display is a 921K AMOLED
-The new lenses will be the 20-50mm and the 20mm pancake
-The 20-50mm f/3.5-5.6 ED has no OIS system
-Both lenses do have a new button, iFn button, it is an extension of Fn button on the camera and you can control the features through the focus ring on the lens.
-The EVF is optional and just 201K (300×224) with 0.83X magnification
-The new external flash is the GN15
-The other device on the National Geographic picture is a GPS receiver and works with google maps
-The camera has 2 select dials, one on top and other around 4 way button
-The camera has a lot of direct access and controls.
-Th the DOF button is on the left side of the body
-This are the dimensions 120.5 × 71 × 34.5 mm
-282gr
-HD 720p with mono audio
-The Auto mode ISO is selectable: 1 step (200, 400, 800, 1600) and 1/3 step (125, 160, 200, etc… until 1600)
-Manual ISO selectable from 100 to 6400

from
http://www.mirrorlessrumors.com/exclusive-on-mirrorlessrumors-the-nx100-specs-and-image/