Here's what I have:
A lambert eyeball with ramp shaders for the pupil/iris. The ramp color positions are expressioned to in-scene curves so I can change the size of the pupil and iris independently. Since I'm the rigger and animator, I decided to forgo checks to keep the pupil smaller than the iris. I can do that myself. I also have a deformer lattice on the eyeball, but I'm thinking its controls may be too dense for my purposes... thinking of thinning those out. Of course your standard look-at control, as well as eyelid open/close controls. Plus a highlight control. The director is going for highlights that express instead of reflect surroundings, so that funny oval with a line through it is the highlight control

Nothing too wild here, but the eyes will be the single-most expressive part of the characters. The result will be similar in style to an earlier piece the director did, pac-man: the musical.
Pac-Man the Musical: A Pacapella Song - YouTube
Edit: There are some other small problems with the eyeball rig that I'd like to fix, but I can live with them and probably have to considering this needs to be done as soon as possible.