Here's one that's never been inked and certainly never made (as far as I know). Ford's slab-sided '49 was available as a Business Coupe, Club Coupe, Tudor, and Fordor sedan, convertible, and wood-bodied wagon. What if Henry II had pulled the trigger for a fastback sedan option?
Here's what it might have looked like, with a few custom concessions thrown in. To start, the wheelbase and track are the same as the sedan and coupe. The entire front clip is unchanged. Bumpers and taillights are the same-side spear too. The fun part begins with the doors, chopped about 2 inches with a 1/2-inch removed from the B-pillar for a slightly angled profile. Ford would have tooled up for a new roof skin and structure, trunk, and so on, but we're using a '49 Chevy skin. A quick eyeball tells me that the stock Ford's backlight is a matching silhouette.
Utilizing the external decklid hinges would be a neat trick and would help legitimize the whole deal. The rear quarters are spared of heavy surgery. The taillight spears are cut out and set aside while we take a vertical slice out of the rear few inches of the quarters, just shy of the apex on top. Pull the end cap from the bottom outward, maybe 3 inches, then fill in a pie slice piece of virgin tin, fabricating a new seam on the bottom. Simple right? Take a deep breath; the hard part is almost over. Some interior structure would need to be rearranged for the new fastback configuration as well.
All that's left is bodywork, paint (factory Sea Mist Green), upholstery (pearl cream yellow leather in 1-1/2-inch pleats), and suspension (probably a healthy C-notch in the framerails). I'm envisioning this sitting on a set of 15x6.50 bias-ply whitewalls along with appropriate '50 Merc caps and rings. Drivetrain is up to you!
Imagine our car in the flesh, done up in this relatively mild custom guise. It would certainly blow some minds! But the real question is, would it still be a shoebox?