The barrel piano you mention can indeed be restored. We have restored
several barrel pianos. They are very difficult to restore. That is
why no one wants to do it.
The difficulty is not complexity: as you notice the piano is a very
simple mechanism. But these instruments always have damage from some
yutz who did a halfassed fix at some point. Also they are so old and
mistreated that they have many other problems.
I had one where the yutz restrung the treble end with all number 17
piano wire. Of course, he broke the plate. The soundboards usually
end up a stack of 4-inch wood slats which have to be glued back
together. They are restorable, but it takes longer than a normal
piano, even if just from waiting for the glue to dry.
The last two we restored appraised for around $150,000 when finished.
Granted, they were 8' tall and had a larger footprint than an upright
piano, but your smaller one will also be quite valuable when done.
They are EXTREMELY rare!
I am leaving for Denver to install a theater organ in East High School
for the next week or so. So don't worry if I do not answer your
mailings 'til I return.
D. L. Bullock Piano World St. Louis