Most people struggle to plan their financial futures beyond the next decade, while those with money and foresight are likely to think well in advance about what they want to leave their children, grandchildren and even great-grandchildren. But what about planning for eternity? It seems too long to contemplate. Yet in the last several decades, states have begun competing with one another for the business of perpetual trusts, which are designed to last forever, or at least 1,000 years in the case of Wyoming. And people have been putting their millions and billions into them, eschewing traditional trusts, which typically end after 100 years.