Actually, exactly that concept has actually been quickly growing in popularity for quite a few years now, it's especially been successful in developing countries like India and China. Small, highly reproducible groups which simply revolve around the core concepts of the gospel. Starfish vs. Spider, etc.
A few years ago, our small church here in Berlin moved from a model where we were paying thousands in rent for a "meeting space" to simply meeting in a living room and sharing our lives. It's been a wonderful change which has really been great, not only (but also) financially.
BTW, an influential book in that regard is particularly Neil Cole's "Organic Church".