Our new apartment, unlike our old, doesn’t have built-in bookcases. We were trying to decide between making or buying a bunch of plain vanilla wooden bookcases when kad had a stroke of genius: library carts, aka book trucks. Librarians use them to reshelve books, but no reason they can’t be the shelves.
We ordered a few standard-issue flat shelf carts from Vernon Library Supplies, though they’re also available with slanted shelves and in various other configurations. In addition to Vernon, School Outfitters and Brodart also have a bunch of different models.