Rugby v Gridiron: Who's tougher?

While I'm talking about footy, I might as well deliver on my promise to discuss the question of "Rugby versus Gridiron: Who's tougher?" The argument I hear from the kids at school is that American football players wear a lot of padding and rugby players don't, so they must be tougher. The answer depends on what you mean by tougher. If you are talking about endurance, there is no question rugby players are tougher. Rugby's constant motion trumps the NFL's seven seconds per play average any day. But if you are questioning their "manliness", their ability to take a hit (which these boys are), you have no case. NFL hits are way more violent than rugby hits. Rugby has nothing to compare to a quarterback getting blindsided, a WR's exposed leap across the middle, or a punt returner getting leveled the instant he catches the ball. Most rugby tackles are after a five metre gain, so players rarely reach top speed. Much of the time, the ball carrier is running east or west, parallel to his tackler, rather than up field--very few head on collisions. This is not to say rugby players aren't tough, I'm just saying don't let the gridiron football pads fool you.
A similar question I get is if I think NFL players could play rugby. My answer: not many. It's a different game that requires different skills and different body types. A NFL quarterback's skills would be worthless in rugby. Most wide recievers are too slight, most linemen are too big. The only NFL positions with a chance would be linebackers, some defensive ends, and maybe a fullback or tight end. Similarly, most rugby players couldn't play in the NFL. If they could, they would be there: it's all about getting paid. The only Aussies in the NFL are former AFL players, and they make NFL squads as punters, Dallas Cowboy Mat McBriar being one example.
I have also heard many students reference a visit to America by the Australian national rugby team, where they played rugby against NFL players and won. I have a couple points to make about this story:

1. AU's national rugby team against some guys who have likely never played (or even watched) a rugby game? Of course AU won.
2. I don't believe it ever happened, certainly not recently. First of all, NFL players make too much money to risk something like this. Second of all, don't you think ESPN would have covered this? I have searched the internet for this story, but have found nothing. Yet I have heard the same story from students repeatedly. It's like an Australian urban legend. The next time I hear it, I'm asking for documentation.