What's frustrating to me is that apparently a modestly priced (for spacecraft) dual-satellite telescope system has been designed that could return images of extrasolar planets like we were snapping pictures of Saturn, but it hasn't made any progress because of budget limitations.

Edit: here's a brief article that gives an overview of a lower-budget, swarm technique being proposed by Planetary Resources - http://www.dvice.com/archives/2012/04/could_planetary.php