I may be wrong because I haven't played it in a while, but I'm pretty sure that most NPCs in GTA4 had a mechanic that told them to get up and limp away if they recieved a curtain amount of damage in a curtain area (usually the leg). More importantly, they didn't do the mentioned 'come back for some more' thing, but if other unarmed NPCs saw that someone - either dead or injured - had left a weapon on the floor, they'll pick it up and give you a go.
This sort of dynamic behaviour was particularly effective at getting you to forget that you are actually trying to outwit a cloud of 1s and 0s, and I was quite surprised / disappointed that Skyrim didn't have something like this.
EDIT: OH! I've just remembered MGS2 and (I think with some NPSs) MGS3, where you can hold a guy up, shoot him in the right arm, which makes him drop his gun, then the leg, then shoot his radio, then put your gun away and watch him panic, try and fail to call for backup on his broken radio, then hobble away for help. It's not technically a surrender mechanic, but it is a pretty neat example of the detail in those games.