Wow that sounds really neat... a great idea! I'd like to see it in action.
Questions... Can you turn off individual sockets so that a small plant gets top light and only the lowest side lights, or are they all wired together? One thing I'm thinking is that the power surge from your entire tree lighting up at once might be a bear... put different levels on different circuits and then time them to come on a little staggered?
I hope you will start a log of your new light tree.