Well, it looks like while I was composing that message there were people solving the same problem. How nice that the cygwin/xfree86 community is so responsive as to be able to post me fixes before I've even finished posting the problem report ;-)
Anyway, "xset r off" does, indeed, seem to fix my problems, and even without turning off autorepeat (which is presumably handled by windows independently). Great. Lev
