Get MIC - although 1/2 the routine is step, the first 1/2 is kick-butt hi/lo.
Also get the CTX series - it has a lot of kickbox and hi/lo in it as well.
Also get the Boot Camp / ME DVD - although it is structured as a cardio + resistance-cycle routine, the cardio premix is a real nosebleeder.
Also get the Step Jump Pump - although it too has step, it also has another hi/lo sequence.
A-Jock