I am so with you on the notion of Severus playing the violin. In fact, there is a Snupin story I utterly fell in love with months and months ago that was something of a period piece. In it, Severus was a famous (perhaps infamous) violin virtuoso -- brilliant and passionate and mysterious as all get-out. I adored the imagery and the description of how he lost himself to the music. Stirring, evocative stuff.
I recall the story surrounding it was quite good but it's been awhile since I've read it, so not sure how well it has aged. Nonetheless, if you are interested, I will dig up the link for you.