If you want to get technical Then Poser's Hair Room has instancing in that you have a couple of hundred strands that you can move about and then populate then rest with clones that come and go. Not helpful for anything except the hair room, but it does sort of exist.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13