Comment 9 for bug 728081

> Any idea for suitable shortcuts?

Not really - maybe leave it up to the users for now?

Personally, I use these bindings in '~/.config/inkscape/keys/default.xml' - they are rather cryptic, but ok for testing (and for my own needs):

  <bind key="L" modifiers="Alt,Shift" action="LayerToggleHide" display="true" /> <!-- L -->
  <bind key="l" modifiers="Alt,Ctrl" action="LayerToggleLock" display="true" /> <!-- l -->

(on my system 'Alt+Ctrl' is not reserved by the window manager (quartz-wm), and if conflicts arise with other OS X system shortcuts, I usually tend to change those instead)