After looking at that video, it sounded as if you had something loose in the drive train, but it stopped and then started again. From reading what you described, it leads me to believe the problem is electrical, it starts to shake then goes away, if it was something within the motor or drivetrain it would do it consistently. I would definitely look into hiring a good attorney with lemon law expertise, they should have documented every single time you were in there, no matter if they could duplicate the problem or not, it is a trail of paper work, which covers you, but instead they just dragged there feet. I wish I lived closer to you, I would have helped you out, but we are about 6hr drive away from each other. Have the dealer call the Nissan techs at the factory, or insist that they send techs up from the factory to look into the situation, since it is clear that there in house techs are not experienced enough to diagnose your problem and fix it. Insist on it, and if all else fails, get yourself a good lawyer, or better yet, report them to the BBB, and contact your local news channel, believe me the last thing they need is bad publicity being reported over the TV.