tl;dr: You'll sell a couple dozen barrels, and a thousand or so pieces of brass (if you have Starline or Quality Cartridge run 25k pieces for a custom head stamp).
But I don't see a big market; and you'll never recoup the expense for the brass, unless you can convince some place like Graf's to buy it.
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I shoot .480 Ruger and .475 Tremor. Both use "handgun" bullets, with the Tremor being able to also use rifle bullets and custom bullets.
The lightest commercially available bullet that is generally obtainable is the Speer 275 gr Gold Dot. They're designed for terminal impact velocities higher than .45 Auto can achieve at the muzzle in a 1911. Terminal performance will be sub-par.
The Barnes 275 gr XPB is a similar story. Designed for higher impact velocities. --And the nose is a bit longer, if I recall correctly. So it may just be too long for the job, while also not feeding (because giant bucket mouth).
The majority of available bullets are 325-500 gr, with long noses; and very few of them would feed worth a crap in a 1911 (if they would even fit).
However, Hawk does offer a custom "auto nose profile" for .475" bullets, for .475 Wildey Magnum. You could probably work with Hawk to cook up something appropriate for the application.
Hawk Custom Bullets
More than likely, your COAL would need to be close to .45 Auto's 1.275" in order to feed and function correctly. In addition, the 'max' COAL may be necessary due to the nose length of the few 'possibly usable' .475" handgun bullets.
Where you would find a magazine and frame that could feed such a thing, I have no idea except for the .50 GI parts from Guncrafters.