Yes, you could cut and re-weld--actually, you'd have to "section" it because you want to preserve both the threads and lower race area mentioned above. Also, you want your weld line to be well below the reach of the stem because, IMO, it's a must to put a sleeve inside--a "guzinta" (you know, one guz inta the other), Best bet there is to start with a piece of DOM and turn it down to a perfect fit, then fill weld through holes drilled through original steer tube and then at the seam. Cut and thread doesn't look too bad after all.