[Tatsu]

Drop me a PM if you'd like. we just implemented a I2c->Analog sensor interface using the AD8652. It's a really easy to use R-2R dac which outputs the binary value from 1mv -> 4095 mV in 12 bits.

Also, if you have PIC programming capability, you could use a I2C / SPI dac and get better performance... not that it matters with the 8 bit OI ADC.