USEFULL LINKS :
quadchamfer vs max chamfer by Pedro Amorim :
https://dl.dropboxusercontent.com/u/93793/Screenshots/1922_px_px.mp4
Possible corner solution for quadchamfer by steffen Unger :
http://www.steffenunger.com/advices/ughyay.gif
This is really old stuff from back in the day