North Korea without a Kim at its head?

What would happen if the North Korean leader Kim Jong-il died? With rumors of him collapsing due to poor health, it's a question that pops into my head.

Will power be bestowed on his heir, making a de facto monarchy effectively a real one? Unlikely, given what I've heard what Kim Jong-il had go through after his father's death, but maybe things could be different the next time around. Will civil war erupt in the country as various factions attempt to grab power after the loss of a powerful controlling authority? Or would war with South Korea be arranged to distract the populace from the loss of their "Great Leader"?

One lurid possibility is that "Kim Jong-il" will never die, even after Kim Jong-il's death, with a succession of doubles posing as a figurehead for the government to maintain power. It may not be so unconceivable, considering that some people think that he is already dead and the person we're seeing now is actually a group of look-alikes. It would be really disturbing if from a hundred years from now "Kim Jong-il" will still be ruling North Korea. I think it's rather unlikely, but I wouldn't put it past them.