Maybe you could stretch the sessions out to an hour. It takes a good 15 minutes to switch from anaerobic to aerobic exercise, so the 2nd half of the 30 minutes you're quoting is where most of the calories are burned. You could triple it of you got up to an hour.
Twice a day, and you'd be burning off 1 pound a week! This of course assumes that you don't build any muscle from any of this exercise, which of course you will. But while the muscle does add weight, it also adds to your static metabolic load, which will help you burn fat ALL the time. So as you add muscle you will loose even more fat just by having the muscle...
Maybe with conditioning you could work up to 3 one hour fuck sessions a day and REALLY get into shape. You may end up breaking a few WGs, but hey, it's all in the name of good health, right?
-G