Stakas is one of the Starcast regulars, and just happens to live in Australia. He made it out to PAX Australia to talk to Erin Roberts about all sorts of good stuff. Somewhere in there it is mentioned that Squadron 42 is currently set as five chapters, with each chapter containing 30+ Missions, working out to 10-20 hours of gameplay per chapter. So the whole single player experience will likely work out to between 50 and 100 hours. We were discussing this in some other thread the other day but I couldn't track down which one.