This sounds like release early, release often only in house. Pixar would be another good example of this; they storyboard the whole movie and other employees "watch" it with in house voice acting it until it's good enough to animate.
Even Apple does this: that's the point of Steve Jobs' legendary tendency to criticize in-house prototypes over and over until he's satisfied.
Not sure Steve Jobs's tendency to criticize is specific to in-house prototypes, though.
See http://www.folklore.org/StoryView.py?project=Macintosh&s... for an anecdote about Steve Jobs and the design of the original Macintosh. I've heard variations of this story for other products, too, so I suspect he's got things structured so he has a final veto on any design.