AvWeek: USAF, NASA Eye Cooperation On Next Reusable Launcher
Interesting article on Aviation Week & Space Technology's website.
To the degree where there is commonality between their projects, this should be pursued. This could include areas like avionics, materials, heat shielding, and other systems. It sounds to me like there's too much difference between the two groups goals to design a common vehicle to accomplish both missions. However, leveraging technology between the vehicles makes sense. I do hope they factor in ease of maintenance in the designs. That alone will greatly reduce the time between flights and the number of personnel required to prepare the vehicles for flight.