Here is a photographic First Impression View of the new PANASONIC LUMIX G X 35-100mm F2.8 Power O.I.S. over at Popco.
What I gather from these photos, like my old Canon EF 70-200 f/4 IS, the zooming is internal. The barrel does not move like my Lumix G X 12-35mm f/2.8. This is wonderful for video shooters who want to add accessories like a matte box.