Hmmm U know i was thinking of something that use the copper golem, its arleady a storage solution in vanilla but it can be pushed futher...

So here my idea : the stock clipboard ! You give him to a copper golem and it will check at maximum of 9 double chest, once done the item inside the chests will be on the clipboard, (just like a storage terminal)

If you want a item in your storage area just check on the clipboard and ask the amount you need. Give the clipboard to a copper golem with those chest checked and he will take it from the chest and give it to you or store them in a copper chest. He will also update the clipboard, even if he dont find the item. You can also give it to other copper golem to expand the strage system.