I once looked at a Steinway Duo-Art on Central Park West in New York
City: Louis XV case, in beautiful walnut; the serial numbers puts
it at 1932.  It had an Ampico drawer with a Duo-Art tracker and fan
accordions.

It seems to me that, rather than produce extended case pianos that can
only be used for players, Steinway and other former Duo-Art marques
would just modify standard-case pianos to make players.  I imagine
there were plenty of spare parts around for both the Duo-Art and the
Ampico mechanisms as the popularity wound down.

Arthur Marino