In more than one place I've seen a munter/mule combined with a prussic as the ratchet point in a pulley system, especially in one of my favorite books:
http://www.amazon.com/Glacier-Mountaine ... 0762748621
It's hard to make out if that red cord is actually tied as a munter on the end but I think this is an example is here:
http://www.summitpost.org/ratchet-syste ... ing/700714
But even ...