If I remember hearing correctly, cardio kickboxing burns HUGE calories!! I'm not a step fan either (though I have them, well, because I can't get rid of a Cathe tape/DVD!), and use kickbox quite often in my personal rotations...I would think you could mix up any of her rotations with running or kickboxing and still get amazing results!!
I think i heard she's coming out with more next year (boxing/kixkboxing, that is!!!)???
MJ