When Microsoft co-founder Paul Allen, legendary aerospace designer Burt Rutan and private spaceflight proponent Elon Musk team up on something, folks are bound to pay attention -- especially when they're promising nothing short of a "revolution in space transportation." At the center of that ambitious goal is a new company backed by Allen, Stratolaunch Systems, and a massive new aircraft to be designed and built by Rutan's Scaled Composites. If all goes as planned, it will be the size of two 747s (with a wingspan greater than the length of a football field), and it will be able to carry a 1