I saw Adafruit has a nice tutorial on how to bit-bang the SPI in Python but I really wanted to use the hardware SPI in Python so I did a little project where I wrote a C extension for Python. I'd never done that before and I thought it was fun AND useful so I wrote it up here: http://louisthiery.com/?p=248&preview=true
You can just check out the code on Github: https://github.com/lthiery/SPI-Py
I don't know if this exists yet but if it does I couldn't find it. Hopefully somebody here finds it useful...