Hand code your epub using CSS to animate. I just finished a Children's Read Aloud eBook which is fully animated only using CSS.
I kept digging until my I found out how to make my characters grow, move, fly in and out all while having the timing right for the automated page turning feature. It's not EZ but very doable.
If you want to see a sample, go to:
Click on View in iTunes and you should see where you can download the free sample.