My vote goes for OS X Ocelot.
Besides Mountain Lion, I think they're really out of cat names.
They may have used up all of the BIG big cats, but there are still several smaller species that can be used.
After that, it's probably time for OS XI which will likely focus on natural gesture and voice inputs. I don't see true "touch screen" PC's, they don't work well, but newer, slicker incarnations of the trackpad or motion based controls make lots of sense.
Going along with that idea -- the trend towards smaller - lighter - faster, maybe something like
OS X 10.8 - Margay
OS X 10.9 - Serval
OS X 10.10 - Caracal