I don't know that I have ever hear of an "Offic1al Size." My originally research lead me to believe that 15" was pretty close, but I am now leanning toward 16.75" based on some pics of the actual pack with a yard stick, with that said the perspective in the pic still might be play tricks. I havben't quite finished the revise templates based on hte new size, but they are coming.
Don't forget you also need to account for the size of the wearer, if your 6 feet then go full size, if your 5'2" then a full size pack will look wrong, so you need to scale to your subject.
As for the file I have CAD files available to whoever needs them, just PM me your e-mail and I'll send the on out. Make sure to let me know what format you need.
Alan