Addressing Adrian's Expansion Issue

Though it is not necessarily the same mechanism, you may wish to take a look at the potential of rotational expansion that you often see in irises and some flora (refer to Arash's earlier research).  This would also be invaluable as you try to develop mechanisms that actually accommodate your expansion ambitions.  Perhaps if you could imagine a direct weight load that would cause a gradual rotation on the centre platform that would deflect a bit yet cause the "petals" or armatures to rotate thereby expanding the surrounding panels. Take a look at the table below for a more mechanical approach (but without the cheesy classical tropes).