The GeneratePlayerDiedMessage function outputs a death message based on the killer, the person being killed, and the object type that did the killing blow, however the list of messages to generate based on the object-type isn't available to add to or change. It would be nice if the game would export the table the GeneratePlayerDiedMessage function uses to the sandbox, to allow people to add some flavour to death messages for those who want it.
Another option, since creating a specific message for every possible game object isn't necessarily feasible, could be to change the function to let it see and use item-types or item names (based on the object-types) as well as creating a way for easy customization of death messages based on those, however that's getting a little more complicated.

+1 Fun. :p