I want to mention again patent application 20110080659 filed by Nikon on September 30th, 2010 for a 18mm f/2.8 DX lens (28mm equivalent) because I think this could be the lens used in their upcoming high-end APS-C compact camera. As I already mentioned back in 2011 when I covered this patent, this lens is not designed for F-mount - the back focus (BF) is 19mm and it needs to be 46.50mm for F-mount. The lens is also very compact - only 58mm from the image plane to the front element. Here is the lens diagram from the original patent filed in Japan (2008-40033):
Based on the above diagram, the lens will most likely have 6 elements in 5 groups.