JC has a good idea about the contract with the donor prior to death- this is similar to the idea of compensating victims of car crashes or other fatal torts prior to death in David Friedman's Law's Order. One problem that comes to mind here- it may be hard to draw such a contract because of certain circumstances that may have to be there for the organs to be salvaged and these odds might be very difficult to calculate (it's one thing to predict when someone will die, but another to predict what organs will be viable for donation when they do).
Another plus with these contracts would be that the donor could specify his definition of death. I understand that people in the medical field have varying definitions of death. And I guess there are laws in certain states that require certain things before someone is pronounced dead. When the law changes from declaring death from when the heart stops for so long to when all brain activity ceases or some other definition, the varying lengths of time have significant effects of the salvageability of various organs. With a contract with an organ company, you could specify your definition- this could help insure that the organs are salvageable. And also provide some legal recourse for family if they are wronged by someone declaring death too early. Jason