Problem solved! Farmland Tractor Supply in Tanget, Oregon was able to special order a bunch of steering shaft and ballnut assemblies for a B6100; it was identical, except the shaft was 2 1/4" longer than for the B7200. I made a spacer bushing to take up the additional length, and it worked great! I was always dinging up my knees with the acorn nuts on the bottom of my steering wheel speed knob anyway; I like the steering wheel raised up a little higher! The assembly (67211-41120) was $190 plus shipping. I had to use several shims to keep the bearings from binding up (2 each of part numbers 66811-41320, 66811-41340, 66811-41350, and 66811-41360), plus the old ones, I think one more each of the thinner ones? If you use the trick of adding a zerk and filling the column with grease, make sure you get the shims right first. I can't believe how easy my steering is now; it must have been binding up and destroying the ball nut bearings ever since I got it used a few years ago.