There are no more 'big cats' names to use except maybe mountain cat (which does not sound interesting at all), and clouded leopard, which I'm 100% sure they won't use due to reasons explained earlier in this post.
One more thing... when Apple is finally done with OS X, and wants to move on to OS XI, what naming scheme do you think they'll adopt? perhaps canines? birds? sharks? or even dropping the whole animal theme, and go with stars, galaxies and maybe natural phenomena. OS XI Volcano, anyone?
Let me hear your thoughts!