It was a hard decision, but I decided to freely release MeoMotion Animator for 2D distortion skeleton game character animation for games. It includes simple example source code for MonoGame (and XNA), SharpDX, DirectX11, SDL2, and OpenGL and editor allows consolidation of projects in exports.
It has a simple interface and allows vertex distortions, and fade-blend animation overlays(for expressions), supports animated part-swapping, time-lined layer reordering, key-part isolated blending, control-z(although not 100% tested), etc..
It can be found here:
http://www.alienscribbleinteractive.com/MeoMotion.html
And editor tutorials are also available as video:
If people like it enough I will later try to add more features. Possibly IK, parametric interpolations, binary exports, and others...