I'm thinking of putting up some cable-suspended shelves. I know where
to get cable and shelf retainers, but I don't know what to use for the
shelves, since they have to be quite wide: total width 164cm, and it's
only possible (read easy) to put cables at the ends. Worse, their
intended use is books, of a fairly heavy kind - say 20-30kg/shelf, for
luck.

What material can make shelves 160cm long, 20cm deep, with an SWL of
100kg, with end support only?

Followup: are the shelf retainers (from Flints) up to that load,
without being so tight as to damage the cable (I was thinking 3mm
cable)?