You really only get bonds from transfers, being out of the realm on tax day, and selling food. With no banks, transfers aren't an issue. With so few nobles and troops, being out of the realm should hardly an issue. With their only region being mountains that are more or less self-sufficient, food sales aren't an issue, and purchasing extra food can be done by camping past the border on tax day to get bonds.
You can still shuffle gold in guilds/temples.
I do hope that the long ago mentioned possible estate buildings do come to play one day. One that spoils be awesome in such cases would be a bank, or recruitment building.