D800E and D4 are full frame FX format, the sensor size is 36 x 23.9mm; D7000 is DX format, the sensor size is 23.6 x 15.6mm; V1 is CX format, the sensor size is 13.2 x 8.8mm.
D800E sensor is 36 MP; D4 and D7000 sensor is 16.2 MP; V1 is 10.1 MP
Here is an image taken with D800E, AF-S NIKKOR 300mm f/2.8G ED VR II and TC-20E III. The image is 36 MP.
Here is the image cropped to 16.2 MP, the image size of D4.
Here is the image cropped to DX format (1.5x) of D7000. As we can see the images of D4 and D7000 are identical. It means, if we decrease the size of the sensor of D800E to DX format, it will have the same pixel of 16.2 MP as D4. But D4 still have larger FX format sensor, a situation similar to that between D3 and D300. In which, both camera are 12 MP but one in FX format and the other in DX format. Thus it will be unlikely that Nikon will ever make another professional camera in DX format. People want to use DX format can simply just put their DX lens on D800.
Here is the image cropped to the CX format (2.7x) of V1.