The folks at Colt might be shocked because they did offer cartridge conversions on the pocket .36cal models. Many were made from unfinished frames as new cartridge guns. All were .38 Short Colt, 72% were rimfire, 28% were centerfire.
Last I talked to Bob Millington, he'd build you a new one for about $1200, plus the cost of the base gun. Don't know if Kirst & Strite do them or not. I know nobody offers a drop-in kit.
But it doesn't perform just as well as the larger 1851/1861 Navies.
Because some of us are obsessed with the very period correct Colt cartridge conversions and all their variations. Enough so that we seek out $250 out of print books on the subject so we can learn about them.