Popping an uber right before sudden death gave me a weird "power fist" animation (the full uber crackling stayed on the screen):
Then when I died I passed the power on to the only person left alive:
One of those weird spy-dead animations... notice the pyro on the right who killed me right when I took the screenie... I guess that was a poor idea:
I'm done fiddling with the images for now, I can't seem to get them to display normally like everyone else's...