Mike Griffin is NASA's newly confirmed administrator. At the following URL you will find his roadmap to Mars that he made prior to being nominated by the President:

http://www.planetary.org/aimformars/study-summary.html

Griffin produced this report with Owen K. Garriott who is a god-like astronaut in the same league with Buzz Aldrin, Harrison Schmitt and John Young. Download the PDF document of the report and check out page 20. You'll see an Apollo Command Module derivative CEV capsule mounted on the end of a Space Shuttle SRB. IMHO, this is a very cunning design using existing hardware with very little development cost. The following quote appears on the Planetary Website:

"To this end, we recommend phased development of the new CEV, with the “Block 1” version designed for LEO access and return only, with a later “Block 2” version suited to the requirements of interplanetary missions. The CEV would be launched on a new human-rated vehicle, possibly based on the existing Shuttle solid rocket motor (SRM), augmented with a new liquid upper stage."

This quote is reassuring because it shows that Griffin understands that his "Block 1" CEV is not suitable as a Mars return vehicle. However I did not see any reference to Lift-over-Drag ratio or entry corridor width. It's possible that Griffin doesn't realize the the basic Apollo CM shape is inappropriate for Mars return. Except for this detail, Griffin's report shows a good insight about what it takes to get us to Mars. My only real reservation is the appearance that Griffin has abandoned Cheap Access to Space (CATs). His SRB trick might get crewed launch costs under $10000/kg. However getting under $1000/kg will require some sort of fully reusable launch vehicle. That development process appears to have been abandoned along with classical aeronautics.

Gary