HONK! Lifehack (HONK!hack ?) :
On Ebay, for around $35, you can get "Kobo" e-ink readers (like a cheaper form of Kindle) I got one and then dragged every PDF from my band's set of charts onto it from my computer... now I have a full set of emergency sheet music, like we have a new friend join us in rehearsal.
It's klutzy in a lot of ways, but beats trying to juggle lots of folders of printouts.