Dropping the Hammer, which is one of Troy's new ones, sounds like a good one to help you focus on cadence for longer duration. Maybe Ride & Stride -- very high cadence work and the sets seem to go on & on. Also, The Sprinting Machine (it deals more w/lower duration/high cadence work, but it's helped me a lot).
I have the same issue, so I've been focusing on high cadence work. I love the hill and strength Spinervals, so I've had to force myself to do the higher cadence ones.