I am a huge fan of cellist Tina Guo. At solo recitals of classical music, she dresses as a highlight performer, but in an elegant fashion. When she is performing with her metal band however, she dresses the part. She's an incredibly beautiful woman in both respects of classical and metal performances. She doesn't let the two cross over because of specific expectations of performers. 

That being said, I love listening to her, and seeing her, classical or playing metal. With her, the music and the visual is what attracted me to her in the first place. 

I guess I am saying, know your audience, and dress appropriately. Convey who you are, and in so much as you are a soloist, convey an accepted level of your personality in your attire. That doesn't mean to be stodgy. 

And it happens in other musical genres and not just classical. When I play as a sit-in gig with a local band, I dress like they do, which is a bit more adult contemporary. But when I play with my band, I dress a little more rock and roll. And when I play celtic music, I wear my kilt. Malleability in one's attire as well as one's performance can lead you to more gigs.