Kodiak, I think you have already answered the question, for yourself. Everyone has a different view of what "ethical" is, and it looks like you have answered what you feel ethical is. Everyone has a different view on this.
I personally can shoot my compound 50 yards, and group the broadheads in a 4" circle. At a big game animal standing broadside, I feel very confident in my ability to put the arrow where it counts. I would never shoot at a running animal.

Soon, (I hope) I will have my new Crusader, and I am sure that my views of an "ethical" shot will change. It all depends on my ability to accurately, and consistantly place shots. Maybe that range will reduce to 15 yards, maybe 35 yards. It all depends on MY personal ability. What I feel comfortable with may be a long shot for some, or it may be a joke to others. You have to be able to live within your self imposed range, and not stray from it, no matter how great the game.