Since I've had my D3x,I've realised that I can set the camera with a 4x5 ratio and get a cropped view in the viewfinder.
The rest of the image is greyed out.
The actual file is saved in the same ratio.
You might think why bother,as you can shoot in 24x36 mode and crop the file later,but sometimes it's handy to shoot in the more useful 4x5 ratio.
What we need now is a D4x with a 35 MB sensor and than shoot in the 4x5 mode and still get a 30 MB file.
Best,
Willem.