My advice to Michael Moore would be to go ahead and do the repair
yourself.  I believe Art Reblitz covers the subject in his book.
Materials should not be difficult to get.

The biggest piece of advice I'd give would be to locate or make
spacer blocks to rebuild the accordion.  I have a set that PPCo
sold back in the day.  If I can locate them, I will give them to
Michael.  Regardless, the dimensions are well documented and fabricating
a set of spacers is trivial for any amateur who knows their way around
a table saw.

If you've rebuilt other pneumatics, a Duo-Art accordion should not be
a huge challenge.  I'd stick with hide glue and leather covering
although I've seen accordion pneumatics rebuilt successfully with thin
pneumatic striker cloth.

Ed Chaban