The Sanguino stuff still works fine. I just copied it all to Arduino 18 after a bit of messing around trying to decide how it would fit into the new directory structure (I'm using linux) and everything appears to be ok.
One issue I did find but not investigate yet, so I am not 100% certain, is that until the program fuses are set to use the external crystal, the programming speed for the bootloader has to be slowed right down to a fraction of the internal clock speed. I couldn't upload the bootloader from the Arduino ide so I used AVR Studio with a slow programming speed and it worked first time.