Sort of underscores the problem though doesn't it? If this hybrid game is going to be enough like League for Leaguies to accept it, it won't be Union enough for Union folk, and vice versa.
I think you'd see ALOT of kicking for touch. You wouldn't see guys like Slater, Hayne and Gordon bringing the ball back into broken defensive lines. You'd need to take the wingers out of the defensive line though which might be interesting, more space for guys to run through.
Then it's just League with lineouts and contested scrums though. Would that be enough for the majority of Union fans?
Interesting to note that the idea didn't take off because League officials didn't want the rules of the game interfered with. They were happy with the game the way it was. You see pretty similar attitudes to the proposal today from League fans, in spite of the obvious similarities between the two codes, and the way League has reinvented itself over the years. I don't know whether that says more about us as fans, or more about the quality of the sport. More than likely a bit of both.
On a side note, that site is awesome