If I was going to run something set in the world/worlds of these books, I'd almost certainly use Mutants and Masterminds, rather than just try to assign statistics to the equipment that the gods and moravecs occaisionally allow relatively normal humans to use. Although a good deal of what the gods do is derived from a piece of equipment, they also have innate powers that regular D20 is ill-equipped to handle.
Mutants and Masterminds, on the other hand, gives you all the tools you need to parallel Dan Simmons work. It can handle everything from non-enhanced warriors on the battlefields of Troy on up to the incredible powers of Zeus and the future-earth's intelligent Logosphere!