Is there a plugin out that gives you more storage space, kind of like a backpack. For instance, say a large wood box has 48 slots, but have it have pages like the backpack. That way you can just utilize 1 box instead of multiple. I saw XStorageUp but that's only to upgrade the smaller storage units(as far as I know) It might be a pipe dream but I think that would be a really cool addition to a server. 

Wouldn't it be easier to just increase your server's stacking rate?

I appreciate the responses, I'll have to check out Storage Upgrade.