As mentioned before, I have been learning Blender and created a character model from scratch. You will find this character appearing in other images from me; it's an android girl I'm creating for a little planned visual novel game. Since such a game is mostly dialogue, facial expressions are important. I've continued to rig and have been experimenting with facial expressions, improving facial muscles and controls. Here are some of the latest outcomes
(original size images on DA).
All generated in Blender, with cropping and organizing using Gimp (and a little Krita).

General facial view, rendered with 80mm focal length, aiming for a serene, and a little melancolic look.

Various stages of surprise and disbelief

Outrage, anger and general growling

Scepticism, curiosity and maybe a less extreme take on surprise or sadness.

Various tests for mouth shapes and more extreme eye/eyebrow positions.

Mischievous expressions, tests of extreme deformation of the cheek and distortion caused by a wide smile.
Overall, I find it harder to produce a realistic and not cringe-inducing happy expression than most of the other emotions.

A tight smile is fine, but an open-mouth laugh is very hard to look natural across the face, and something I still need to work on.
Feedback is appreciated!
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Griatch