When a physicist was tossed the Jem And The Holograms plot to look over, he determined that it probably wasn't feasible, as it would require a mile-wide mirror orbiting the Earth, along with a monstrous projectors and power source. Plus, the people on the project came back with a question of their own: What does Allah look like? It seems like getting it wrong could have caused some problems.
By the way, The Washington Post found that the Air Force started looking into this technology in 1994, though who knows how long they stuck with it, or if they're still waiting for the right advancements go come around. Still, tuck this away: If a deity suddenly appears in the sky over a city at some point, you probably should remain skeptical until it performs a miracle or two.