Eric built an EEPROM daughter board that fits on the ISCP header of the Bus Pirate. This design had been floating around the forum for awhile. It’s not officially supported in the current firmware, but code exists to save and load BASIC scripts from an external EEPROM daughter board.
Get a Bus Pirate v3b for $30, including worldwide shipping at Seeed Studio. Adafruit also has the Bus Pirate and probe cables in stock and ready to ship. Each Bus Pirate sold supports further development.