I drew up a Ruger Revolving Rifle many years ago (before the new model came out) and was going to build one from a Super Blackhawk, but when Ruger brought out the New Model I didn't want to modify a now irreplacable Old Model SBH. I couldn't see how the New Model hammer could be converted to pull rather than push the mainspring, as I had visualized the hammer/strut setup to work from the rear rather than down into the pistol grip of a handgun, so I never redrew it as a New Model.
I might yet sacrifice an Old Model if I can find one that needs to be restored to begin with, and I have some spare time to invest.
I did, many years ago build a Remington Revolving Rifle from a Navy Arms handgun, cap & ball, before Uberti made theirs.