A friend of mine has replaced standard I2C EEPROM with FRAM.
He says it is code compatible to I2C EPROMS, the price is near the same, but the performance is much higher (no write cycle limitation, no write delays (like 2 ms for I2C EEPROMS), can be used as 'non volatile' SRAM.

Sorry about the type, I did not remember.

Franc