This thread has inspired me to break out my trusty Delsey hardshell rolling case and take a tape measure to it. Since I'm flying next week, it was about time anyway.

Not counting the spiffy 360-degree swivel wheels, it's pretty much exactly 9 x 14 x 22", empty or full. The wheels take the height up to 24". The shoulder bag I use as a computer case is about 1" bigger in all dimensions than the 6 x 11 x 15" limit for those, but I strive not to overstuff it. So I guess I'm a bit of a hog. But I manage 2-week European trips out of those 2 bags, and I do generally check the bigger one on the way home.

I've only been asked to check the rolling bag once, by KL at LHR.