In issue 252 of PC Pro magazine, I covered how to use Minecraft Pi and Python on the Raspberry Pi to create a shelter. Intended as an introduction to Python and how it can be used via an API, the final script is provided here and contains plenty of configurable variables for creating shelters of different sizes and shapes out of various materials.
Other resources:
Martin O’Hanlon’s Minecraft Pi page is excellent
The Raspberry Pi Foundation’s official guide to getting started
Craig Richardson’s table of API calls
Raspberry Pi Spy’s table of Block IDs