This is the way how Fuji Super-CCD files are processed (this method borrowed from dcraw.c):
- raw data is not 2:3 but stretched in one dimension (different for different cameras)
- color order is not rg/gb, but green columns and r/b columns

On processing:
- entire image is rotated 45 deg to get normal bayer pattern with diagonal greens (it is also unstretched to get 2:3 aspect ratio)
- standard debayering is used
- output rotated back and cropped