The common anecdote is that Google used Angular to make the the Doubleclick advertiser interface, which is just as big if not bigger than the Wordpress admin interface. It turned out to be great, with much less lines of code than what they had before (GWT).
Regarding Backbone + Angular in a large project, I wouldn't touch that code base with a 10 foot stick.
Great thanks. My perception up until this comment was that Angular was more of a mini-tool for MVVM for use in little widgets, and not really able to be huge.
I wish it was advertised more what large projects using Angular and that they are actually architected completely with Angular.
I'm not sure what you mean by _really able to be huge_ -- a large single page app? a site with a huge number of pages? # lines of code? I don't think there are any hidden limitations in Angular proper -- in fact it will allow you to organize source for a "large" project very well, and will perform very well -- but you have to be careful with scope digests (i.e. don't try to "compile" a bazillion objects -- but that is mainly common sense)
A lot of articles I originally read/skimmed with Angular didn't really tout it's ability to organize large codebases... I got the impression is targeted toward smaller projects, whereas Backbone they market themselves in your face "we will clean up your large codebase".
Regarding Backbone + Angular in a large project, I wouldn't touch that code base with a 10 foot stick.