I briefly experimented with using the system "Take snapshot of canvas" action with CocoonJS. I actually did have success in sending the snapshot to WebStorage and then using the "Load image from URL" function of a blank sprite object and entering the WebStorage.LocalValue contents. Interestingly, I had to Flip the sprite for it to display properly.
Anyway, figured I would post and see if any of that is helpful. :) I'm on the latest C2 release, r143, and CJS 1.4.