i know there's some more demos at
http://nightly.ckeditor.com/13-05-19-13-05/standard/samples/
but i think it would be great, if there was a way to test customizations:
i can already download an editor with my selected plugins, what if there was a button "DEMO selected"?
ideally, it would be possible to edit configure.js too...
maybe use sth. like http://codepen.io/...