I thought I would shoot this over to see what y'all think.
I invented and patented The String Stash. It's the best way to store your guitar strings. Strings are kept rust-free and organized. It rolls up and stores in the compartment under the neck in your case. Make changing strings suck less!
Looks to be a great little system for storing instrument strings.
In the operating theater, we make little roll ups just like these to hold surgical threads. Very handy and although yours are made for a different purpose, and intended to last much longer, I have no reason to suspect they'd not function as admirably as the ones we make!
I may have overlooked, but how many pockets are there and about how many strings will a pocket hold?
Do you have models for instruments of different number of strings (fiddle / mandolin / guitar / lute /etc) and different string lengths (bass / cello / archlute)?