I think that this is a good application for secret-sharing (a way to take a secret and split it into
n pieces, of which
k are required to reconstruct it).
One wouldn't necessarily want to split a secret amonst one's family (because families can feud), or even put the shares into the hands of people all belonging to one legal jurisdiction (because the odds of even a good government going evil within one's lifetime are uncomfortably high). But one could, say, pick three family members, three friends and three colleagues, distributed over the world, and then split the secret amongst the subgroups {family 1, friend 1, colleague 1}, {family 2, friend 2, colleague 2} & {family 3, friend 3, colleague 3} such that two members of each subgroup must agree to recreate the subgroup secret, and two subgroups must agree to share the actual secret. Assuming a reasonable amount of independence between the individuals, this should be okay.
In practice, this would probably have to involve sending each person an annual notice with his share, as well as detailed notes on how to recreate the appropriate secrets and information on the others who have received a share. And of course one would need to think hard about how difficult it would be for a second or third party to suborn the system (in the example above, all that's needed is for two family members and two friends in the same subgroups to live in the same oppressive legal jurisdiction: one subpoena later it's all over).