Writing to SPI/I2C devices through FT232H

Hi all.

I'm recently working on a kinetic project involving a number of hobby servo motors controlled by a I2C PWM controller PCA9685. (or some of you refer to the famous Adafruit 16 channel 12-bit PWM/Servo Driver - I2C interface )

I realize it would be very nice if I could hook up Grasshopper to the FT232H chip breakout board that I'm using as the USB to I2C interface. It is pretty cheap and have much higher speed than trying to use a Arduino to perform the same function. I'm wondering if anyone have a similar interest in developing or using a function like this?

Or if you have seen it being done already?