2nd men on the moon..
Seems to me, if all the private space venturists, got together on a manned moon mission, it would solve the budgeting and save NASA from doing it. Another thought is that some may be mistaken as why we need to go there. Mars is going to be the largest challenge man kind has ever accomplished so far, and as in war, you need to practice and test new machines and materials before blasting off toward that big red rock. But that is only one reason a return to the moon may be important.
IIRC the Sally Ride report described the best strategy to making the trip - I think she wrote this before ISS was built, but that doesn't matter - she proposed that doing a frog lily pad approach was the way to go - 1st establish a good space station in Earth orbit, then a base on the moon to support the mars effort ( low gravity saves fuel - and can act as a construction and science base.) Only then can you make that final hop to Mars. If you can't survive on the Moon then you have no business completing the Mars journey. I wouldn't doubt we could go back there easier than we may think.
We could construct the lander and orbital command ship at the ISS, then in the last launch, only a fuel booster would be sent to marry up with the Lunar Landing ship to finish the voyage. Thought should be given to putting a structure on the lander that could double as a beginning structure to a moon base. This way every piece and part goes toward the goal. The lander doubles as a launch port just like in the LEM design, but perhaps it could include a robotic design that would later help build the Moon research station. This is going to be left behind after the module launch so why not take every advantage possible. Then robots could be used in an attempt to prepare a ground base to make a human return to a semi permanent research center possible.
The possibilities seem endless, and I get excited just brain storming new ideas. I'm sure someone could easily come up with a much more genius method that I could ever dream up. Lets GO!!