Great books make "epic" films?
No doubt there are problems doing direct translations from book form to film. But as the Lord of the Rings has shown, you can follow the book almost dead on and still have a great movie. The devil is in the details, you know.
Memoirs of a Geisha and Tristan and Isolde don't seem like the typical epic films but they both have the "epic" visual style. Narnia has buzz but not as much as I would have liked to have seen because the film looks great. And yes, there are Christian overtones, yes the cast is mostly white and the issues discussed in the story are binary, good or evil, get over it people its a story written in 1950. These facts always start some witch hunt or protest or greivance to the MPAA.
*Tristan and Isolde's story is a Romeo and Juliet type of story, with star-cross'd lovers and warring countrymen and the like. I've read the French version but I've heard that the story is originally Celtic.