What a clever invitation. I love the 5 as the shadow. I also love that because it seems it'll be called the iPhone 5. Eat a dick to all of you pedants who were crying about others calling the next iPhone the iPhone 5. Looks like your pedantic posts backfired.
No, not yet!
The more that I think about it, the more that I am starting to believe that the next iPhone will be called "The new iPhone" with the 5 in the invite meaning the event next week will celebrate 5 years of the iPhone brand (via iPhone stats over the past 5 years, and the unveiling of the next iPhone).
I could be wrong but Apple's usually a bit more clever with the invites. I think the 5 = "iPhone 5" is too obvious.