So of course someone did it with Star Wars, but George Lucas' army of droid lawyers had the video taken down shortly after it went up. All that exists of the experiment are images. I didn't have much going on back when the video was first posted, so I skipped around some and watched chunks of it. It was a mostly useless video, but watching the series in one shot was somewhat enlightening.
First of all, while the movies began at the exact same time, the opening title sequences didn't sync as well as I would have thought. Imagine six orchestras are locked in a closet and all of them are trying to play their own Star Wars theme loud enough for their version to be heard above the other five. If instruments could fight, a symphonic gang war would sound like the opening titles to all six Star Wars movies playing at once.
Some of the moments that mirror one another in the narrative happen at roughly the same time across movies. Luke falling after getting his hand cut off in The Empire Strikes Back and Vader tossing the Emperor into the pit in Return of the Jedi happen almost simultaneously. The Death Stars in A New Hope and Return of the Jedi explode within a minute of each other.
And there was an odd pattern seen throughout the video: There's almost never a moment when watching all six movies at once that R2-D2 and C-3PO aren't on screen. When they exit from one movie, they enter another. It's purely coincidental, but after a while, it started to make me think the real story of Star Wars was two robotic Forrest Gumps who happened to wander into every major historical event in the galaxy.