Well, it could be possible. An example would be the models 69, and 686. They could use a Switchable 2 piece barrel for both Calibers, and supply a Second Cylinder. On a personal note, I think it would be easier to just have two different guns LOL
It would be nice to have a revolver that had a quick detach cylinder. Combine that with a barrel system like the Dan Wesson. That would make for one fun revolver