Want to know some more about Apple’s upcoming tablet device? You’re in luck. We’ve received the scoop from our reliable source—who correctly called the iPod nano 5G, iPhone 3GS and Chinese iPhone 3G months ago. (1) Apple has created at least three separate prototypes of its tablet computer. Let’s call it “iPad.” (2) Version 1 was designed with a 7” screen, which was judged to be too small. The latest…