The grand list of similar (free) projects:

http://easeljs.com/

https://github.com/biilly/doodle-js

https://github.com/fairfieldt/xcjs

https://github.com/batiste/sprite.js

https://github.com/mrdoob/three.js

https://github.com/ysimonson/canvas.js

https://github.com/davebalmer/jo

https://github.com/lostdecade/diggy

http://gamejs.org/

http://www.aframejs.com/

http://gamequery.onaluf.org/

http://www.kesiev.com/akihabara/

Does anyone have any experience with one or more of the above, to help narrow down the field of viable frameworks?