Thanks for all the suggestions guys.
Originally Posted by
Bikedued
It got turned into $850 cash from one of my cohorts. My wife took $500 for savings, and I got the rest
Boy does that sound familiar. Except the percentage of my cut is always substantially smaller.
Well, it looks like my options are narrowed down thusly:
1. Ream out the steerer tube to 22.2, and then the Nitto long-reach stem would fit.
How hard would this be? Could I do it with a hand-drill and large bit? Or would I have to go to a machine shop?
2. Buy the Nitto long-reach stem and grind off 1.1 mm, and then it would fit in my steerer tube.
Could I do this with a standard work-bench buffer/grinder, or would that be too imprecise?
3. Get that "stem-raiser-adapter" which pastorbob linked from Harris (for $19.95), and then the Nitto long-reach stem would fit inside that.
The only problem is the resultant stem + adaptor might end up being a bit too high for me.
4. Keep an eye out for vintage 21.1 stems, with longer (110-130mm) reaches.
Assuming they made them that long, which hopefully they did. 
By the way, this thing rides so smoothly, I can't believe it, even better than my modern Bianchi steelie. Talk about absorbing the road!
John