You could go about this any number of ways, but here's my $0.02.
When I look at this fabric, the FIRST thing that comes to mind is a high-waisted, knee-length or calf-length skirt... the kind that swishes when you spin. You could wear it with a peasant-top or cap-sleeved blouse (linen would be fabulous!) and pull off a rather elegantly ethnic look, without being bothered by your neck strap.
Mind you, skirts are usually sewn on the bias, for the sake of volume. This fabric isn't nessicarily prohibitive of that, but keep in mind you'll have to match the pattern where those fat lines would meet at the seams-- think "V" shapes.
If a skirt doesn't do it for you, I have some cautionary advice. The sheer size of the pattern is going to make fitted dress tops a little fussy to match up.
Avoid halter-style dresses. I find they're very flattering on pear-shaped women, but your instrument is going to tug it all out of shape, and you don't want to look like you're about to fall out the sides of your top on stage.
... in other news, you could consider going with a traditional
ethnic pattern, not just something ethnic inspired. What about this
OOOOH AUGH, I've gone and inspired myself
, now. To the sewing room, with me!