I'm not entirely sure if this goes here but I have often seen people use death animations in their machinimas without the Grim Reaper showing up. So my question is, where can I find a death animation box?

* bump*

Well I guess its a little late but, I've found a pose box, or somethin. I could give you a link.
Its Called Poses:Fight Night in SimLand... but your sim will stop posing in about 5 seconds if you make them pose.

I hope this helped enough (unless you've already found one)

I have done some research and you can actually download a hack or mod for your grim reaper to not show up during death of a sim