im actually building one right now... 4x7, 8 flip up casters, 8 legs, legs are laminated 2x4s with half laps for the horizontal framing... glued to the horizontal 2x4s with a couple of #8 2-1/2" construction screws for insurance... gonna do a flip up miter saw and have tablesaw mounted to it with the top being outfeed for tablesaw.