According to GW2 wiki, anyone can create a guild directly from the guild pane in the menu. There is no need to visit one of the Guild Register NPCs in the cities. It only costs 1 silver, which you can get in a few minutes of playing. Or, with mail being instantaneous, we could probably get one person 1 silver really fast. I'd be surprised if it took 15 minutes once in-game.
I think several of us are going to be camping out 3 hours before the headstart officially begins, since ANet mentioned today that servers could be up anytime during that period. We'll get it!