I'm planning on writing a mod that will be a color-coded detect life/death for stealth characters. If the player would kill the NPC from sneaking in one hit, the NPC should glow green. If not, then it should glow red. I imagine the second part will just be copying a lot of what the existing Detect Life effects do, but I'm not sure the best way to do the first part.
Obviously the game has to calculate damage between two actors somewhere, the question is if those methods are available to us.