It hasn't even been out for a day, but there are already hints of the next iPad in the current iPad's OS. BoyGeniusReport did some digging around in the iPad OS file system and found some interesting seeds burried pretty deep. They found references to "iPhone3,2," "iPhone3,3," "iPod4,1," and "iProd2,1."
iProd 1,1 was the original reference to the current iPad. The current model of the iPhone is 3,1, while the current iPod Touch is 3,1, and the current iPad is 1,1. What the new references reveal is that not only is Apple working on the next iPhone, iPod touch, and iPad (no shock there), but that there will be two versions of the next iPhone.
Products with different storage capacities do not get differing referal numbers, so its anyone guess how the next iPhones may differ. One possibility could be that the differing iPhones may be an AT&T-specific iPhone while the other could be a T-Mobile or Verizon-specific iPhone. The only thing these product reference numbers tell us for sure is that in today's day and age, the newest piece of tech you buy is virtually already outdated.