The Collector& Shelving is a fully adjustable system of shelves and credenzas, designed by the high-end American fabricator Amuneal.
Muuto stacked shelving system, via DWR
Wall of shelves made from book boxes--maybe use wooden crates like this for storage under loft?
High/Low Modular Bookshelves : Remodelista using IKEA Prant Boxes and Binder Clips!
ikea prant boxes - think i pinned this before but couldn't tell they were held by bulldog clips - i like that!
Designboom: noir vif: modular bookshelf (interlocking, no fasteners needed!
I have moved a few times and those crappy big box book shelves work fine for about a week, then the cheap particle board shelves begin to sag and go ahead and try to.
No Built-Ins, No Problem: Customizable, Modular Bookshelves that Don't Require Putting Holes in Your Walls