I'm all for making special suprises for my kids, and even spoiling them at christmas, etc.. but I think I'd draw the line at ensuring they didn't have to wait in any lines... even a super line. It's this 'someone will do it for me..' is why this line is so intolerably long in the first place. People are taking the consequences away from those that would normally bear them.
If a 4yr old couldn't wait in a 2hr line.. the line wouldn't be 2hrs long... but instead by making all these substitutions we enable the line to grow beyond it's natural balancing point.
I totally understand your position as a father - and it's difficult for a 4yr old to understand those kinds of trade-offs of spending such a great portion of your day in the line so you can't just leave it to her. In my world... I would probably wait in line for her as part of her birthday 'gift' if there was a way in that queue to not have to walk the entire line pushing through to catch up