Does anyone know how to Run an OnHit block on a corpse? Or simulate it? I tried just the standard block, and got no results-- so unless this is a glitch at my end, it seems it does not work if the actor is dead...

True. Attached scripts do not run on dead actors. If a script is part of a magic effect, it only runs on the actor 'once' with no looping.

I have done this for a dead dragon in my mod "Duke Patrick's Dragon and the Sword of Might".

The player had to hack into the stomach of the dragon to retrieve a quest ring.

You will need to look at my script in that mod for all of the details, but basically I used set pos on a special invisible and inaudible rat to hold the rat in the same place as the body of the dragon.