If you've gotten the races out, look up a good machinist, and see if they might re-machine the bearing track. Wouldn't last forever, if original was surface-hardened, but it's the lower compenents on a headset that really take a beating. Though others will shout me down for this suggestion: maybe as a last resort the "internal" flanges could be cut off, and the head tube machined to take a standard headset. Might also have to cut steerer tube, and extend threads, but whatever it takes to keep an old bike going.