Is this a "mainly for you" setup, or do you plan to have other people/groups over regularly? If it is basically just you, then gameroom3 is fine. However, 3.5' for two people back to back is barely any room, not to mention people couldn't get by. If you plan to have people over regularly at all, I would opt for gameroom2. You have the same walkway space, but it only needs to accommodate one player.

I know there is always a temptation to squeeze in one more, but at a certain point not only does it start to look like a horder's place, but it starts becoming less functional.

If you were dead set on getting that 9th game in there, I think flashinstinct's first drawing is the best. If you did blow out the closet, you could get storage containers to put parts/tools in and store them under the game. This would give you 9 games in the most functional layout.