Inspired by all this talk of the next Bugatti being a Panamera competitor...
Hope you like it - it's a bit of a rush job, but a total nightmare to do.
I've 'chopped' the back and extended the nose so that it looks front engined; used a reversed and modified front door window to make the back door window; extended the area behind the front door to make a back door and changed the profile of the scoop so that it fitted the new rear door. I also changed the location of the door handle very slightly to make it look more balanced. I did try adding a back door handle (in both suicide and regular) but I could make it look right, so 'it's got a hidden handle or solenoid popper'.
ETA: please click through the pop-up - it looks better full size.