I used the 'calpac' on the weekend at ITU LD. I prefer to call it 'lunchbox', because this is what the Commander calls it.
I'd post pics if I had them but my bike is still packed up. But, the capacity is much larger. The well goes slightly deeper, and the sides are a bit wider and taller. Also, the end closest to the seat tube where the flap used to be is no longer tapered. The top of the lunchbox has cuts in it so you can access different areas, not just the area through the flap as it used to be. The other advantage is that it's fixed as one unit with 2mm hex screws to the existing threads in the frame. So it's not going to come off straddling the top tube at traffic lights, or whenever this has been a problem.
I had 10 gels and my blip box in the lunchbox for the race, and perhaps could have fit 11-12 with more particular placement. It's a nice improvement.
http://www.josh-amberger.com/