Daniel Martinez Lara seems to be getting quite well into Blender. He has now made this simple but great leg rig. It uses very few handles (only around 2-3) without compromising the functionality even the slightest.
Daniel also did a quick little demo video that also shows how the rig enables quick rearrangement of the pivot point of the foot/leg. Click here to download the demo video. Let's hope we'll see more similar rigs in the future.
Thanks to Daniel Martinez Lara for making this available to the Blender community!