A while ago I managed to create a fully adjustable face emulator using redstone lamps, so I figured I should share it here.
It's broken up into 3 segments: A mouth (shown below in diamond blocks), a nose/upper lip (shown below as the iron block), and 2 eyebrows (shown below in gold blocks). In the mouth, every single lamp is controllable. You can control whether or not the nose/upper lip is on/off, and the eyebrows can be individually toggled.
As many as you want. I have it hooked up to a piston-feed-tape right now that has ~20 different faces it cycles through, but it's easy enough to hook it to something else so it can emulate whatever faces you want.