Just a quick example, one of my builders implemented a "Halo flood" infection. Here is what it looks like:
mpe &Cthe carrier explodes and a group of infection forms appear.&W
Now the intresting bit goes more indepth:
mpecho a combat form grows and grows and gets back up to its feet as a carrier form.
And my favorite part....
mpecho an infection form jumps into a corpse
mpecho and turns it into a shiraqui combat form.
mpecho and turns it into a shiraqui carrier form.
I know with out more detail is hard to see whats going on, but you should be able to get the idea of death progs (at least on npc's).
Note, I do think the "if otypehere(corpse_pc)" does work.... so be careful with that if you use it. Been awhile since I've used this however.
**EDIT If you look at the swfote limbo.are file for the arena you can see an example of death_prog in a room, however I don't recall if I've ever seen it work.
*** Edit again: I'm still looking for a death_prog on an item... So far nothing.