Lucasarts trademarked the following titles last week:
INDIANA JONES AND THE FOURTH CORNER OF THE EARTH
INDIANA JONES AND THE QUEST FOR THE COVENANT
INDIANA JONES AND THE KINGDOM OF THE CRYSTAL SKULL
INDIANA JONES AND THE LOST CITY OF GOLD
INDIANA JONES AND THE CITY OF GODS
INDIANA JONES AND THE DESTROYER OF WORLDS
"City of Gods" seems most likely to be "real," I think.
However, I am particularly fond of "Destroyer of Worlds" as it directly references Oppenheimer's quote at the Trinity test, "I am become Death, the destroyer of worlds." Given the setting (1950s! Cold War!) I'd imagine that the nuclear threat will be front-and-center. I like the way that title combines the mythic (the Bhagavad Gita) and the scientific (A-bombs a-go-go).