hmm there are
nvidea tech demos out there, where at least over 1000 (complex) models are instanced in different animation states (ofc i do not know the restrictions of the code in this video - i'm pretty sure that this system maybe relativly limited).
But to get to the gist of my post: As you already said it's "pretty" easy to implement Instancing for Sprites (as there are a lot of articles about it, in the net), would it be possible to implement this a little bit earlier? Would be a wonderful way to create a much more realistic Gras-System