Here is an updated pdf on the latest work on the New Worlds Imager and it has a proposal for a new Worlds Discoverer. The New Worlds Discoverer is proposed to be developed and launched in 2013. It could detect earth size plants out to 30 light years and analyze the spectroscopy of jovian (jupiter) sized planets. There are probably 10,000 planets within 30 light years. This system is about 35 m in size. It would have one starshade.
In 10 years, (2016-17) the proposal is for a $2-3 billion New Worlds Observer. It would be 150m in size. It would have two starshades. It could detect life on earth size planets by analyzing the spectroscopy.
Then for 2025, the New Worlds Imager. Lunar based or in space system that would have 1500km long baselines.
These are great systems that should be developed.