I know many Salon groups that are 2 violins, cello, Clarinet, Bass, Accordion, and Piano.
The instrumentation of various salon ensembles depended on the changing cast of players as in Vienna, Berlin or Paris tradition. The piano is joined by the typical standing violinist or Primas, along with a second compulsory violin, viola, cello, bass, various wind instruments, harmonium and sometimes later accordion and percussion. These formation changed as various people were playing or not.
On of the most famous salon violinists was George Boulanger http://www.prima-carezza.ch/boulange.htm
. Most of these pieces had many parts which were played or not depending on who was available to play or not.