Here's an interesting article from Gramophone magazine about a different kind of crossover - between period and modern instruments. - written by Jane Gordon, violinist in the Rautio Piano Trio, who plays with several period instrument orchestras including the Orchestra of the Age of Enlightenment, English Baroque Soloists and Arcangelo.
She says "Period instrument orchestras, which at first specialised in performing only Baroque and Classical music, are now broadening their repertoire, exploring performance practices of pieces written in the late 19th and early 20th centuries. For example, this season the OAE performed Mahler's Second Symphony and, last season, soloists such as Viktoria Mullova and Isabelle Faust played Brahms and Mendelssohn concertos respectively on gut strings. Two worlds once so distinctly separate, have begun to merge."
I recently heard Isabelle Faust play an all-Bach programme at the Chipping Campden Festival with Kristian Bezuidenhout at the harpsichord (he's perhaps better known as a fortepianist). Apart from being a wonderful concert, with such enormous musicianship being shown by both performers, it was interesting that my companion asked "is she playing a modern violin or a period instrument?".
find the music you love