My grampa had a 41 REM Derringer that I was thinking of doing this with.
Still have it, but, the arm pin where the barrels tip up are in REALLY bad shape.
I took it to a gunsmith and he just started shaking his head. He opened up a book/catalog and I ordered a Cobra Enterprises derringer in 38spl (long bore) right then and there. (had to wait 4 months to get it, but, its a nice gun)
44Henry rounds work the same way I think...
For the Sharps BP carbines, there are "similar" cartridge tubes with a flash hole in the back. Most folks found these "interesting", but, the cases didn't seat a bullet well as all.
(when I got to shoot one, I asked its owner if he had thought of putting some nitrated paper under the bullet as a way to seat it better...]
I think other collectors refer to these as "one hit wonders"