the traxxas tubes help some, the hollow pillow balls help, tekno rx box, ti hinge pins, alum pivot balls, and the pin tires on hurricain wheels are the lightest available i think.
IN the research I did about lightning my revo I was told not to. Basically do what was said above, but beyond that it is not worth it. The power that the racing mills put out (os tm/tz and the 3.3) if the rig is any lighter then it will be harder to control. Get yourself a good setup and practice practice practice.
About the best and only piece of aluminum I would recommend is the front skid plate and maybe the bumper. Once you do all of the above and get the weight down you may actually have to add a little weight up there in the front to keep the nose down. Slayden had like 2 or 3 oz up front for this very reason.