Over a period of time the silence from OBL will be as effective as, maybe more effective than producing a box of bones. They'll never find the bones anyway.
The mystery of not knowing wuld bother me more then if I saw proof that he was still alive through some video that showed him holding a newspaper with today's date. I want him dead and I want to see it with my own eyes. If all of the sudden GW went missing and the Taliban was proclaiming they killed him, what do you think the reaction would be?
Oh an what abut that scum Mullah Omar?
More effective. The choice is between a dead martyr and a hiding coward.
There will be more rumors of sighting BinLaden then there are of Elvis.
He will have worked at every convience store in America, delivered everyone's cousin a pizza, and driven taxis in every city.