I can see the merit in your concept, but speaking for myself, if I was going to limit myself to a small revolver for defensive use, I'd prefer a Model 36 S&W with the round butt and a 3" barrel. Reasons are, it's lighter and a bit handier. Plus, I've learned that heavy-ish for caliber bullets work better for serious stuff than lightweight bullets, which points me more towards the .38 Spl.....Yeah, I realize that when comparing loads between the two that 110 grns is about like 115, and that 124 is about like 125....but a 158-160 LSWC like I'd be using in that sort of a situation just ain't going to get enough of a running start when used in conjunction with that puny 9MM case.....Now don't get me wrong. I like the 9MM cartridge, particularly the 124 FMJ NATO (+P) version. Thing is though, I got's a FN High Power for that. It holds 14 Rds and I can hide it on my person just as easily as an SP-101, so then there's that.
DGW