Ronson Piano Hammer Co. can make hammers to match any historic piano.
I have restored several such historic instruments with non-standard
hammers and they worked perfectly and were exactly the same as
originals.

I have used Ronson hammers exclusively for all upright players for
several decades now.  Their hammers are closer to originals than
any other source.  See http://www.ronsenhammer.com/ 

I would _never_ reuse antique hammer butts in a Violano as it requires
a good piano and action to play next to a violin with so many classical
rolls available on that instrument.  Violano restoration calls for
a mostly new piano action.

Doug L. Bullock
St. Louis Metro
http://thepianoworld.com/