... as usual, in the shower! This might be of more interest to Panasonic that Oly, considering their 4K video focus. I suggest 5760 by 4320, 24.8MP. Here's my thinking: 4320 is the vertical resolution of "8K" television (what NHK call Super Hi Vision). A 4:3 sensor with this vertical resolution, used with an anamorphic lens to get 16:9 or even 2.39:1, could use the whole sensor, and scaled to 2160 vertical resolution for 4K would also give better colour resolution (because each pixel would then be derived from a GRBG 2x2 Bayer pixel group). The processing flow would be Bayer demosaic, downscale to half vertical and horizontal (2880 by 2160), and then set metadata in the file to change display aspect ratio to unsquash (which would be used by either player software or by the import code of a video editor). Without an anamorphic lens, you'd crop the centre 16:9 area to get 5760 by 3240. Rescale this by 1.5x to get 3840 by 2160, television standard 4K. This will require a major increase in the power of the DSP engines in the camera, but I don't see this as beyond what Panasonic might put in the next gen Venus engine in the GH5.