Just watched the entire demo. First time I heard two people present a product together - definitely makes it a lot more interesting and much less monotonous. After the first 30seconds, I went "pfft, live reload isn't new." But I'm glad I stayed till the very end because it is indeed so much more. It looks very promising, especially if you offer app hosting of some kind (or make it easy on Heroku etc.)
I am curious about the security aspect of writing to DB directly via the client but I'm sure you've thought of it. I love the 'add less', 'add coffeescript' feature. Can't wait to try this out soon.