I think there is a strong possibility at this point. Ford put it in the bulge mustang to test out a manual controls pack, and possibly to test a future engine combo in the mustang chassis. They also developed a car specific intake manifold for a reason. They could just destroke the 7.3 about an...
If you watched the video, the ford rep said the car was a test mule the 7.3 control pack with a manual trans. They also had a prototype of an intake manifold for the 7.3 that will fit under the hood of most cars.
If Ford decides to build a 4 door mustang, I'd welcome it. If it allows ford to keep the coupe/convertible alive, then so be it. I just hope they don't do what they are doing with the 2 door F150. Some of the better more desirable options on the truck are not available in the regular cab, they...