I can't tell you how disappointed I was once I purchased the ENTIRE library, only to discover the premixes were not on them and that you can't pre-mix your own workout.
I know that during the RT 2007 - that was one of the "coolest" features of the whole "download" thingie. The way it was explained, we would be able to create our very own workout routine mixing whatever segments from any of the vids to create our very own custom workouts. Obviously, I failed to make sure that option was still available when I purchased the library. And seriously kicking myself since I already own 90% of the library.
I know you can jump to different parts of the videos with the ipod, but let me tell you...it is a nuisance to be scrammbling/fuddling with the ipod when you are in the midst of what you plan as a killer cardio routine.