As far back as the piano industry goes, the piano factories never
built the piano bench.  Many customers ask this question.  The reason
is so that a piano manufacturer could concentrate on building a fine
instrument, I guess.  Actually, in the beginning all manufacturers
including Steinway always had someone else build the bench.  One of
the most famous manufacturers were the Tonk Piano Bench Company.

As the piano manufacturing companies would produce the piano they then
would send their information on to companies like Tonk to manufacture
a matching bench.  At the turn of the 20th Century, in 1900, when a
customer purchased a piano, they also had to purchase the bench
separately.

Piano benches come in all shapes and sizes with as many as 25 different
leg designs and a multitude of finishes and colors.  There are oblong,
Squire and many round and roll top types available now.  There are new
ones, used ones and antique ones available.  You can buy them from as
little as $20.00 and as much as $1,000.00.

I think piano benches will be around even long after the piano.  We
currently have sixty-eight pianos in stock and well over 300 benches
and stools.

Kim Bunker - Orange Coast Piano
http://www.playerpianos.com/usedbench.html