Weeeeeell, I'd design
1. a solid frame revolver based loosely on the Remington New Model Army of 1858.
2. made of all-stainless steel.
3. with coil springs.
4. maximum chamber volume of around 40gr of FFFg.
5. quick-change cylinder via a simple locking bolt.
6. heavy enough to use as a club.
7. barrel options of 5.5 and 7.5 inches long.
8. hexagon-ended nipples so that you could use a regular small-size wrench if you lost the dedicated nipple key - with nipples in s/s as well.
Oh, wait a minute, didn't somebody already make something a lot like this? And then, for some unaccountable reason, stop production a few years ago?
tac