Dear Mr. Knighton,  Steinway is the only brand of a 1910 upright piano
which has a chance of selling for more than $1000.  An upright player
Steinway is worth several thousand when restored.  _If_ you care to
restore the instrument with an original player, the Welte-Mignon
component parts are out there, salvaged from other old upright pianos.
Please be aware, however:

1.  Music rolls for the T-100 "Red" (German) system are extremely
rare;

2.  Music rolls for the Welte Licensee action (American, 1920s) are
plentiful, and the player also plays standard American 88-note pop
rolls.

3.  A qualified reproducing piano technician will charge several
thousand dollars to restore and install a reproducing player action (of
any make) in your piano, not including the costs to fabricate missing
components.

4.  A complete reproducing player action, non-restored, will probably
cost a few thousand dollars.  When these actions are sold it's usually
because a fine Steinway grand piano with an exceptional art case is
under restoration for a collector.  (That might be why your upright
action is missing.)

4.  Very little published technical information, such as one would need
to fabricate missing parts, is available for most player actions, esp.
for the German Welte-Mignon.

Both Welte systems, German and American, are capable of reproducing
extremely nice piano music.  But so are the competing American
reproducing piano brands like Ampico and Duo-Art.  Any player action
can be fitted into a piano which formerly had a player installed.  As
always, it's only a question of time and money!  :-)

Best regards,

Robbie Rhodes