The Fleischers' "Poor Cinderella" from 1934. Done in beautiful colors and rotoscoped to perfection. Rather longer than a regular cartoon but justifiably so. I would have sworn the Fleischer animators were doing acid as mind-warping their Betty Boop cartoons were but this was before Sandoz Laboratories invented acid.
[video=youtube;v-bjZcFfuq4]http://www.youtube.com/watch?v=v-bjZcFfuq4[/video]
[video=youtube;v-bjZcFfuq4]http://www.youtube.com/watch?v=v-bjZcFfuq4[/video]