To pull something like this off is proof of how valuable technology can be in creating larger scale productions on smaller budgets. I came across this video a few weeks ago and was instantly impressed at what these 3 graphic designers were able to accomplish in recreating D-day with visual effects. Clearly these guys had a fair amount of experience and good computers to work with, but you wouldn't expect the result to be so polished based on how they start out. It's interesting to think how the amateur side of filmmaking, with YouTube and digital technology, is going to change and really allow anyone to make better and better films (if they actually care to do the work that is). Mind you, this isn't an amateur production, but in the future the strategy for filming scenes like this will probably be more and more common, and the number of people able to do this on a personal computer will only increase.
This video is pretty entertaining whether or not you're into the production side of filmmaking. The work speaks for itself, enjoy!