Maybe you remember my first shulker storage system, with 4 slots but expandable as much as you want !
Here is a version, with another type of selector. 64 slots, with 28 shulkers / slots.
Pretty big, maybe not usefull to have that much to store, but we have it x)
If you want more screenshots, ask !
If you have a way to make it more compact, post your solution !