"Science Mission Directorate at NASA Headquarters, the chair of the assessment, Reta Beebe of New Mexico State University, offered a set of recommendations to NASA, including:

...Move forward on “Mid Rovers,” wheeled robots more capable than Spirit and Opportunity but less complicated, not as expensive, and not as heavy as the Mars Science Laboratory to be launched in 2009...

...Mid Rovers would be geological explorers, dispatched to evaluate the geological context of specific sites and search for organic compounds at targets identified by prior missions. As currently envisaged NASA’s goal is to fly two rovers for a cost approximately equal to that of the Mars Science Laboratory mission—now priced at $1.5 billion. "

http://space.com/news/060706_mars_report.html

Cool beans!