This is one of our experiments to see how far in developing front-end/client-side apps designers can go, and how to improve the workflow between developers and designers.
It's a super-early prototype, and it doesn't handle lots of things, but we thought it would be great to get more people commenting on it earlier rather than later. Is this something that if easily integrated would be useful for you?
We're note sure if it's a product, but maybe it's still useful to the community at large.
Looking forward to the feedback! http://youtu.be/8gTLwMesXrs
And oh yes, this is my first post on DN, thank you for such a nice place :)