A Create addon and storage mod that simply adds new tiers of item vaults. It also adds upgrades to help you move between tiers and a config to adjust the number of slots each vault block has. It also adjusts Create's item vault's default slot count to 32. The config for it it is still respected though, so for your existing worlds make sure to change the value in Create's config manually!
The current default slot counts are:

And here is how upgrades work:

A gold vault was also planned and would have been an alternate path starting from Create's item vault. It was going to have the same number of slots as Create's item vault, (now 32 instead of the previous 20 by default), but instead of a max size of 3x9 it would be 4x12. The code for all that is pretty much already in place, I just didn't want to make the textures for it. So basically, PR's are welcome ;)
Icon coming soon, dw.