Showing the text size change option - unfortunately this does nothing to music, which is treated like a simple image. This is on the "regular" Kindle.
On the Kindle, this is as big as the music is going to get. See thumb, regular sized, for comparison. You couldn't even see the notes on the screen if this was sitting on a music stand.
It should be noted that I have never had to plug a regular book in to charge. :)
On the Kindle DX, you can turn the music sideways through Landscape view, but trying to zoom on the image reverts it to page view. It will not get bigger. Wouldn't it be great if it filled the page left to right and divided the image/page in half vertically?
Side by side comparison of the KindleDX, with the music as large as it will display, next to a regular piece of music. The Kindle music looks squished left to right, and just isn't big enough. Sorry Amazon, I wanted to like it.