I successfully interfaced with the Adafruit interface board (Adafruit 16-Channel 12-bit PWM/Servo Driver) using only two channels of the the Sparkfun voltage convertor to get up an I2C connection (SparkFun Logic Level Converter Bi-Directional - BOB-12009). These are both quite inexpensive--the combo is less than $20--and small. I converted to 3.3V using the 3.3V power supply available in the breakout and this is sufficient to power the logic on the Adafruit board, although you will need a separate 4-5V power supply for the motors (the Adafruit board has separate power inputs for that). I also added a 1000uF capacitor to the Adafruit board to handle surges from the 9 servos in my Familiar.
Still working on getting this working from Node (I will post my progress on that here later) but the Arduino library works if you make a minor edit: at the top of the header file it redefines "Wire" depending on the platform it detects, but it's only set up to detect Unos and assumes anything not an Uno is a Due. This does the wrong thing for a Galileo, so just clobber that and force it to use "Wire". This same code works for the Servo shield as well.