Jerson: That's a good idea. As long as I can somehow clock the data into the shift register then toggle a line to load the current state into the DAC then that should work perfectly (I will do some reading on this). I can get hold of parallel DACs easier too! Thanks

Henrik: I work with PIC24FJ64GA002/PIC24FJ64GA004 chips. It's possible to fire 9 bytes at the SPI module in one go. The first byte moves straight to the shift register leaving all 8 slots in the FIFO available.