The sketchbooks could be opened up on make-shift shelves, or on another type of furniture, such as narrow tables. They could also be placed inside the wooden vinyl/magazine type of boxes, such as these.
However, the idea that appeals to me the most is simply opening them in some way—either on a shelf, or hanging as on the other examples:
Of course, there is also the option of hiding them behind a protective glass, but that does not appeal to me. It reminds me of a museum, certainly not the feel we want to evoke in our exhibition.