Hi, here's a mouse rig I built a few months ago for a project. I was trying to make something to resemble flat cut-out pieces of paper. To that end, all the shading was done with surface shaders set to a constant color and applied to different polygons (the paper texture in the image was comped over a render). It lets you cheat poses like crazy, take certain liberties with the geometry, and really stretch some things to a point that wouldn't look good with a regular shader. For example, he can open his mouth really really big (scale the CornerLf/RtControl to round out the mouth corners). If you do this, look at the spans, they're totally wrinkly and shredded, but it doesn't matter, because you can't see the bumps in the surface because of the flat shader.
Uh... what else...?
-He's very squishy. His whole body is in a lattice, so you can really stretch him around if you want to (see BodyStretchTp/Md/BtControl), and you can rotate the lattice to stretch him in any direction (see BodyStretchControl).
-I'm not sure if I like the facial controls as a separate mask off to the side, but in some ways it was kind of necessary because the whole body is in a lattice, and making the controls follow that would have slowed the rig down a bit.
-He's got pretty good stretchy limbs, and controls to make the arm bend as a curve instead of as a sharp line (see the softKnee attribute on the FootLf/RtIkControl, or softElbow on the HandLf/RtIkControl).
-You can change his colors all in one place if you open up the OptionsControl in the attribute editor.
To download, visit www.aaronwalsman.com (http://www.aaronwalsman.com), and click anywhere on the splash screen. Feel free to mess around with it, animate it, pick it apart, do whatever... but non-commercial projects only.
Have fun, and happy animating,