The rumors were correct, and there is now an additional screen size for iOS: 320 x 568 joins the original 320 x 480 iPhone and 768 x 1024 iPad*.
It’s unlikely that the game will directly support this layout. Sure, 88 more pixels would be nice, but King of Dragon Pass is a landscape game, and extra width isn’t as useful in most cases as extra height would be (most scrolling is vertical). The original art was at a 4 x 3 aspect ratio, and already doesn’t always nicely fit the 3 x 2 iPhone.
* Purists may note that the iPhone 5 has a 640 x 1136 pixel display. Technically this is true, but from a design standpoint, it works better to think of 320 x 568 pixels, with the possibility of fine detail.