When considering designing a low cost low tech home defense DAO revolver I gave some thought to the best cartridge options and decided that a .32 ACP on the smaller size frame and 9X19 on the larger frame would be the best bet.
Its simply easier to find .32 ACP than it is to find .32 S&W, and theres a wider variety of bullet types to be found. A .32 ACP chamber will also accept a .32 S&W so theres some interchaneability. The .32 ACP being semi-rimmed makes headspace no problem.
One could go with the .32 S&W long for that matter, but I figured to keep the cylinder short and compact.
For the 9MM revolver I'd figured on case mouth headspacing and simple cylinder pin pull cylinder removal and extraction for both models . A house pistol or purse gun is unlikely to require rapid reloads, or have spare rounds easy to hand, and the pull pin system would make it more difficult for a youngster or one unfamilar with the revolver to load it without permission.
A auxillary cylinder with loading stand would allow loading with BP and lead shot (no.1 or 000) with a shotshell primer.
Federal once manufactured a 9mm revolver cartridge with rim, similar in concept to the .45 Autorim cartridge.