Can you do kickboxing? Or is that too hard on your neck? If you can do kick boxing you might like Kick, Punch, & Crunch and Legs & glutes.
This will give you a great cardio workout, as well as another great lower body workout.
You also might really like LowMax - it also is a step workout with blasts - like Imax 3. Don't let the Low part of the title fool you, it is a great workout.
Rythmic Step is another great workout - and it comes with Imax and Max. Intensity cardio - 3 workouts on one dvd....pretty sweet. I LOVE rythmic Step - no blasts, it has several longer step routines and then at the end she puts them all together. Really fun to do when you don't want to do any blasts. The other two workouts are high intensity/high impact workouts....really get the HR up! It is an older workout, but still up to Cathe standards of excellence.