I see from searching the net that this has never happened. Is there a known reason or is it simply that it hasn't happened? I am not super familiar with ZDP, but is it because ZDP and M4 carry many of the same characteristics? I really love my Delica 4 in VG-10 and I have a renewed love of my GB1. I was just thinking about how impressive a Delica or Endura would be in M4.