I've been doodling with a screenplay idea based on "Rendezvous with Rama" for several years now, having crafted an outline and written several chapters. I had no idea anybody was seriously considering making this into a movie again, let alone someone as notable as Morgan Freeman. Not being in the movie production industry, I highly doubt any submission I'd make would be taken seriously, but... maybe it's worth a shot.
My take is not totally "true to form" with RWR, but is still founded on the principle of an object entering our solar system that is first deemed as the "doomsday asteroid" based on its trajectory towards Earth, but then it is discovered that its on a controlled course... an artificial object. But rather than a single team sent to rendezvous with it, board, and explore as quickly as possible before it leaves the solar system, a different scenario unfolds. One that I think would work better for movie material.
In my version, RAMA is sort of a variation to "Contact". Rather than an intelligent species beaming technological data to construct a communications device, they have sent RAMA to seek out intelligent life that is deemed "ready" for first contact (this is something that is revealed later on, after contact is made with RAMA). It is a sophisticated long range probe, capable of folding space, but with no sapient life on board. Anyway, it is supposed to assume an orbit around the sun and be reachable from the Earth using our present day spacecraft technology. But something goes wrong (I won't say what the cause is) and instead RAMA crash lands on the moon. It then becomes a space-race for 3 different space agencies to attempt getting to the moon first and stake claim on RAMA--The Europeans, a Russia-China alliance, and the USA. I've worked out the details as to who has the head start and the stresses/conflicts that happen along the way. One of the teams will get to RAMA and be able to explore it... but there will be a time limit, for other reasons than as previously defined in Clarke's book. It will also have enough material open ended for a sequel or two.