That hackathon got through 47 demos in about an hour - 60 seconds for a 6 hour hack was actually probably the right amount of time.
The fixed setup that Alexey proposes in his article is totally the way to go. I totally agree with him when he says not to plug in "somebody else's laptop into the projector." He is correct when he says that "Pain this way lies."
Frankly, the only reason we were able to pull off the TwilioCon presentations is because we had 9+ people dedicated to them: 1 MC, 4 presentation assistants (2 per podium), 1 A/V guy up front, 2 A/V guys in back (1 to run the switching equipment, 1 to run the timer), and 1 other A/V guy to mix the sound.
(A good A/V tech is worth their weight in gold. Make sure you always let your A/V techs know how much you appreciate their work.)