We have gear vaults, jewel vaults and seed vaults, how about a storage shed where we can put unused housing items until next Christmas or Summer or whenever.
Craftable storage sheds is a great idea, although the attic is probably intended for that purpose. It would be nice to increase attic space. What about giving each house a separate attic with 100 (or more ) items? It doesn't make logical sense to be able to buy a new house, but the attic space doesn't increase. Each house has independent space for inside/outside, so I would think it is technologically feasible to do the same with attic space.