This is a controllable gun bot which I designed and created some time ago.
Click on the image to get to the download.
The limbs of the machine recognize with the ground, thanks to python and some floor constraints.
I created a very simple ragdoll which registered the ground and transmits it to the armature bones with the help of some helper-empties.
This Bot works perfect in Blender 2.66 except that the normal maps are not supported, i think this is a bug.
Here is a conceptual drawing
3DHaupt
3DHaupt 