Scent-Lok's most popular light headcover seems to fit on fat old noggins pretty well. Even with it pulled across your face, you can breathe and hear better than before.
It has a 20" neck relaxed and is stretchy, and it seems to have a good bit of headroom.
Side note from Joe at BigCamo: "I have a fat head, and NO headgear gets on the site without fitting me. This passed the test, for me."
Now go kill something!
Realtree Edge, Mossy Oak Terra Gila, or Mossy Oak Country