Some automated way to do timed bonds would be interesting. A way to give an item a face value and a time to maturity in either in-game time or IRL time. The selling price would then be determined between players, as is the case in real life. Whoever has the bond at the maturity date gets the cash (assuming the account has the cash), but players can trade it around as they wish until then.
Simply implementing this could solve a lot of the issues facing Nuismatics economies. How do you get money into the economy? Have the admin buy bonds from players. Need to take money out? Sell said bonds back or offer bonds TO players. Players need money for a venture? They can sell bonds to others to finance it.
The behaviour would be similar to a frognote, if frognotes are implemented, but I think it'd be easier if bond-notes were their own item. Especially if you want to implement the option of coupon payments at regular intervals.
