Lord of Light is probably too complex to allow it to be adapted into a film without serious butchering of its themes. For example, look what happened to
Dune. In fact, several of the themes (such as the wheel of life and technological reincarnation) and Zelazny's use of "anachronistic myth" ended up in the new
Battlestar Galactica. That might be the nearest you'd get without causing rioting in India for apparently insulting the Hindu and Buddhist religions.