A short while ago, SparkFun was selling a few Pocket Geigers from www.radiation-watch.org. The Type 5 is meant to be used with a microprocessor and they have already written a python driver, making the Raspberry Pi a perfect target.
I designed the case to snap together with a tongue and groove. It holds together really well but I suspect it would fly apart if you dropped it.
I posted the software on Git and he STL's on thingiverse.
I consider this project finished knowing I haven't worked on it for much more than a week. There are a few flaws that I could fix, but I doubt i'll get around to it any time soon.
If this project gains any traction, i'll add more detail. It doesn't seem like there are many of these Pocket Geiger Type 5 out there.