Inheritance and Bitcoins
nlocktime transactions are probably the closest thing you have at a protocol level. 

Essentially, you can make a signed transaction that pays a bunch of your relatives on January 1st 2016. If you should die before then, the transaction goes through and they get their inheritance. If you are alive on December 31 2015, you would publish another transaction that invalidates the first transaction. If at this point, you want to continue with the same estate plan, you can publish another transaction for July 1st 2016 that pays out the inheritance. And again, on June 30th 2016, if you are alive you would publish another transaction that invalidates the TX about to be published on July 1st.

You can do this as long as you want and a similar transaction can be used in place of a trust (X gets some amount of bitcoins on their 21st birthday). You do have to be careful about this, as the bitcoins you're dispersing must not be moved in any way on the blockchain for the nlocktime transaction to work.