Here's the final board (v6) that will be going into production (click for big picture). No big changes and it's pin compatible with all boards since v431, so all current software will run the same and there's no need to upgrade for people with boards since v431. The main thing was better labeling and other cosmetic changes, but here's the full list.
* Even smaller!
* Has holes in the corners so you can screw it onto the gondola
* Optional extra pair of pull-up resistors (R9 and R10) on the I2C port, in case you want to add more sensors
• Fully labeled, including part numbers
* SMD power regulator, smaller and easier for mass production.
* Added an extra pair of .1uf capacitors in the motor ports to reduce noise.
* Added a solder jumper (very tiny) so you can select if you want to read the ultrasonic sensor in analog or PWM mode.
• Changed labels north, south, west and east to front, back, right and left.
• Solder jumper to the 5 volts of FTDI cable (so you can power it from the FTDI if you want)
• Better traces
• Changed the ICSP position (the port was a little too close to the IR sensor on the previous version, and it was hard to get a connector in there)
• Power switch before power regulator and motor controller. (the power switch was after some electronics in the previous version, which could slowly drain and kill a LiPo if you left it plugged in long enough with the switch off)
You can buy the boards here
Eagle 5 PCB and Schematic files are here.
Assembly instructions and component lists are unchanged from the previous version.