Not sure about the Guitar Hero bit, but there’s a really nice, albeit very expensive, e-ink “sheet music” device. Product name is Gvido (not a typo). I’ve been using it professionally for about a year. Clunky UI, but hugely nicer than carting around books and sheet music. Form factor is more like traditional sheet music size than is an iPad, and it opens like a book—two side-by-side big, non-backlit pages. Turn pages with a Bluetooth pedal.