Thank you for all the responses.  A new belt has been procured, but
something else needs repair, as when the owner started it up, they
smelled something rubber burning, and it doesn't have enough "oomph"
to rewind the roll.  (I wasn't around, this is what he reported to me.)

We did identify the frame maker, and when I have time to spend with
the piano, we'll see what all has gone awry.  There are apparently some
piano action wear issues too, so I'll have some work for a day!

David Dewey