great way to make adjustable shelving. minimal metal ladder style struts with wooden chevron supports. simple and lovely. Ico Parisi, 1957. (the following images are from "Italy: Contemporary Domestic Landscapes 1945-2000, by the italian institute for foriegn trade.)
how to make a log look modern. marco zanuso, 1949
way before vitsoe. vico magistretti, 1946
suspended bookcase by Ernesto Nathan Rogers, 1958
another interesting suspended shelving unit, the Veliero by Franco Albini from 1938
a nice setup from the 30's. as minimal and "invisible" as shelving gets. i especially love the pared down rolling library ladder.