I see a number of people here using multiple EZ-B on their robots, if the reason is just running out of port lines and number of servos etc, then there is a really good alternative.
Many moons ago, long before the dawning of the EZ-B, the first AIMEC:3 used the SD20 (I2C 20 channel servo driver) chipwww.robot-electronics.co.uk/htm/sd20tech.htm
Using the SD20 requires only 2 port lines of the EZ-B (I2C bus) to control up to 20 servos!
Another big advantage is that the SD20 handles all the servo control overhead, so not only does it release a lot of EZ-B port lines for sensors etc, it also releases the EZ-B from having to generate all the necessary PWM pulses. With the SD20 the EZ-B only has to send one servo position command across the I2C bus and then the SD20 does the rest.
At around £6.50 per chip (and resonator), its quite a low cost alternative, also the same company do ready built servo control module boards.
Hope this is of help.
Dave, I know you have been using multiple EZ-B on your B9, if you want to try out the SD20 then I have a spare that I can send over in your Bosh servo package, let me know if you want me to add it?