Actually, you might have been right after all! I swapped yet another
fuse in from a different position, and I got two of the windows back up
before that stopped working too. Then I swapped in one of the spares,
and it worked for a bit too. When it stopped working, I just gave the
fuse a bit of a wiggle from the top (didn't pull it again), and now
they're working again. I spoke to our mechanic, and he was dead set
that the switches we the most likely problem. But the working/not
working didn't correlate at all to what I did with the switches -- only
fuses.

But this is not very satisfying, it's working now, but I don't feel
that I really fixed anything. Do the fuses oxidize a bit over the
years, even as the sit rubbing in their sockets, and this a higher
current fuse would see the problem perhaps first? Or does this point to
loose wiring underneath the fuse panel?

Of course the radio stopped working now too, but I suppose I can't have
everything.

We're slowly proving all over again something my father told me years
ago -- automotive electrical problems rarely have anything to do with
logic, so don't be logical when you try to fix it.

For what it was worth, while I had a bulk of the stuff off the door, I
pulled the inside panel off and had a look -- the ground must run back
into the body with everything else -- the only wires that split from
the bundle off the switches go to the power window motor -- there's no
grounding inside there that can lose contact. Except for the cosmetic
carpeted bit, I think I got it back together again too! I even had a
part left over, which means I did it properly (it was some odd stiff
kinked metal rod with a little brass bit slid onto it that was just
laying in the bottom of the door. Maybe that was for the radio :)

Cheers, and thanks again!