That Pendagron Pictures version I mentioned earlier is an actual page per page literal translation of the book, which is why it's so long. It's the most accurate to date, but the production values are terrible. Still, despite that, I prefer it to Spielberg's version. And I know it's technically not a period piece, but sometimes things just do so well the way they are. The historical context helps serve contrast to the overall situation. Watching them trying to overcome their odds with canons rather than modern jet fighters and other modern weapons is more entertaining.
Here's an idea. If they wanted to move the story to America, they could have set it during the Civil War, with sides coming together to combat the invasion. The backdrop and technology needed to tell the story is there, much like the technology available in the book. That would have made for a more entertaining version of the story set in America, without it feeling anachronistic.