Also get a small rimfire insert in 22 LR or 22 Magnum.
Harder to find, but closer to a true double rifle could be a Cape Gun with a left barrel insert. I often considered doing this with my Sauer cape gun in 12ga and 8X57JR. A double 8X57JR would be a natural with it's moderate pressures and rimmed case.
Hunt with Class and Classics
Religion: A founder of The Church of Spray and Pray
Acquit v. t. To render a judgment in a murder case in San Francisco... EQUAL, adj. As bad as something else. Ambrose Bierce “The Devil's Dictionary”