Space Pragmatism points us to an article (link now broken) on the new president of the X Prize Foundation. This article states that the foundation plans to start additional X Prizes in the upcoming weeks in a variety of areas. The article did not mention any space prizes. The Genomics X Prize was already started, and the X Prize Foundation web site mentions their intention to start prizes in the areas of energy, environment, social, medicine, water, poverty, and space. It also has a lot of detail about the planned Automotive X Prize. The Silicon Valley/San Jose Business Journal has an article about a fundraiser for a dozen new X Prizes. An article at the Auto Channel has other details and some comments by the organizers. A number of celebrities are expected to be at the launch event. I wonder if the nature of any of these prizes, whether space-related or not (and although I agree they should sponsor prizes in other important areas I would expect them to continue with space prizes, too), will be such that they can be shown in some way at the X Prize Cup (as a competition, or at least a booth exhibit)?
Later: Here is an interview (link now broken) with Tom Vander Ark, the new president of the X Prize Foundation. In this interview he discusses the possibility of a Lunar Lander X Prize (presumably separate from the Lunar Lander Centennial Challenge), and in the near term energy, automotive, and health prizes. A New York Times article suggests that the Automotive X Prize may be for around $25 million.
I would also suggest following the Ansari X Prize with a similar but more ambitious prize. For example, have similar rules but requirements for significantly higher flight, more passengers (or just payload), or faster and more repeated turnaround. I certainly don't consider space access to be a solved problem yet ...