List of faces here.  Have picked the skull one, though the clown would be pretty cool as well.  Should all decide on one though.

http://www.ofpec.com/faces/index.php?action=list&game=ArmA&page=0

How to add into game :

1. go to "My Documents / ArmA 2"
2. place the .JPG picture there, named as "face.jpg". File size should be below 100kb
3. launch the game, go to Player Profile and select Custom Face