So have any real world applications successfully used this as a framework?

It looks interesting but I see any moderately complex web app, i.e. more than CRUD, hitting a wall of complexity when using CouchApp as a base. You eliminate so called "fragile custom code" up until the point where the framework doesn't support something and you need the custom code anyway, except now there is the overhead of getting custom code working together with everything else. At which point you wonder what was the point?