The one piece aluminum frame is a great idea, but I don't think casting is the way to do it. As mention in several comments, correctly preformed welds are in fact the strongest points on the frame. Due to the heating/cooling of the metal during ALL casting processes, this frame is undoubtedly super stiff, but precariously brittle. Also, watch out for the edged of the I-beam frame, I bet they're hellacious on the knees. Now, if someone were to MACHINE a one-piece frame, that would be something worth talking about...