Apple (AAPL) is now less than a month away from unveiling its sixth-generation iPhone, and analysts are tripping over themselves with excitement. That excitement is spilling over to investors of course, as shares of Apple stock hit an all-time high on Friday thanks to “iPhone 5” hype and rumors surrounding the “iPad mini” and Apple’s purported upcoming HDTV. Just how big is the next-generation iPhone going to be? According to FBR Capital analyst Craig Berger — and just about every other Apple analyst on the planet — really, really big. “[The iPhone 5] has the potential to generate the most promising device upgrade cycle in Apple’s history,” Berger wrote in a recent research note. “We calculate that the device represents