I can take it past that for my own project but was hoping for a sample to get me going! 
Any luck getting it going? I have used my Arduino and I2C to interface to an accelerometer, I could provide suggestions on making the connection if that would help.
Where did you purchase your PCA9685? I am looking all over the web but can't find a supplier selling small quantities. I would love to have a dozen but the minimum quantities are around 1k.