Would it be possible to show us a photo of your fabrics, as to help guide you in the right direction.

I have done a few chevron quilts where the pattern "wanders", like a melody across the page. This might appeal to you.

I love this simple pattern for showcasing themed fabrics. I've made it several times.
https://1.bp.blogspot.com/-iXQ4EELCM...0/IMG_7788.JPG

Just a thought.......have no idea what your fabric looks like but would a string quilt work?...my vision is basically a black and white quilt with strips of musical notes , piano keys and other musically related objects and always using a white strip in the middle of each block.

The BQ quilt is a good option for fabrics to tell a story and is defiantly modern in style. The name of the manufacturer is Maple Island Quilts. If you want to find them on line, here is a link with all of their patterns.

https://mapleislandquilts.com/

You say you have been collecting musical fabrics. Is it fat quarters or yardage? How many different fabrics do you have? Could we have a picture of the fabrics please? Is there a specific instrument she likes?

The BQ patterns are wonderful for showing off theme fabrics. I have only used the original BQ. You could make a quilt with squares of the musical fabric cut at 6 inches and make matching 4 patches, 9 patches or whatever other block suits you. I searched for modern musical quilts....Maybe one of these will speak to you. https://www.bing.com/images/search?q...tern&FORM=IGRE

Edited to add: This lady has several websites listed for musical ideas http://www.bellaonline.com/articles/art1122.asp

music theme quilts, some good ideas here!
https://www.bing.com/images/search?q...lt&FORM=HDRSC2

Several years ago I made a wall hanging for my granddaughter that is musical notes alternated with Puss in the Corner blocks. I don't know if it's still available online but it was from Fons and Porter's Love of Quilting March/April 2010. It would have been a freebie pattern.

What do the fabrics look like? Are they all fairly small patterns? If so, any pattern will work. If there are one or two larger prints, then you may want to consider a pattern that uses a larger center square so you can cut those prints bigger. It doesn't have to be a complicated pattern, a churn dash would work fine for a some larger prints. Depending on how many prints you have, every block could be different and just use the same color for the background to tie it all together. To figure out which background works, audition them. Lay a dark, medium and light on the bed and lay your prints across them. Leave it for the day and every time you walk into the room see which one catches your eye first. If you want more of a 'musical theme, you can quilt the centers with a basic musical note. Please post pics of what you pick. (Your friend is a very lucky person!)

Here's my music quilt..
 

I have been collecting music fabric for years, and wanted to also do a red/white/black quilt. The pattern was the theme quilt in our guild, so I killed three birds with one stone.