Hiya.
Janx; I didn't mean to come off so negative...Christmas just does that to me (I don't like it, sue me...
).
Anyway, a long time ago I did something similar; "Hero Points" so PC's could get temp bonuses when they needed it, and you could spend a certain amount of them to dictate *how* something happens (re: you kill a bad guy standing on a thin bridge over a chasm filled with lava...you spend X amount to say you finish him off face to face with your sword in his belly as you whisper "I want my father back you sonofabich"...or you finish him off by chopping off his head as they both fall over into the lava below...or...). One thing you could do was spend 'all' your remaining Hero Points to guarantee an outcome, but at the cost of your characters life.
It worked ok...but after a while it just felt, well, "forced" or sort of Deus Ex Machina.
I may go another route; maybe go "in reverse". Think of it like one of the quotes from the movie Ghost Dog (awesome, btw):
"Even if one's head were to be suddenly cut off, he should be able to do one more action with certainty. With martial valor, if one becomes like a revengeful ghost and shows great determination, though his head is cut off, he should not die."
So, if a character dies, maybe allow a roll of "X" (don't base it on level/hd...heroic sacrifices are not the purview of the powerful...)...say a roll of 1, 11, or 20 on a d20. If they succeed, they can carry out one final task, more or less regardless of dice rolling. i.e., "I say
Not on my watch, and not in my backyard!, and tackle the bad guy over the edge, down into the lake of lava!".
In that way, the character is already 'dead', but has a chance to do something heroic. This clears out any mechanical schinannigans that players may be tempted to try via use of 'hero points' or what have you.
^_^
Paul L. Ming