I wanted to use the Raspberry Pi in this project because it is a miniature computer that could replace the big laptop I use to control the vest. Originally, because I wanted to make another box, I made a Python program to control Adafruit 12 PWM port LED Drivers but Python on the Raspberry Pi is too slow to run them. So for my second attempt to make the Raspberry Pi (that I purchased from Element14) control the vest I sent the startup and controller commands to the Parallax Propeller and let it do the hard work to control the Adafruit 24 PWM LED drivers in the original box.
Currently my Raspberry Pi can control the vest and pretty soon I will have code written for it for gaming. I have also 3d-printed a case for the Pi to prevent me from frying it when I handled it.
9/28/14 Update: See the journal entry "Gamer Vest - Feel like you are in the game!" and code and video updates for more on the gamer vest.