Music Theory Textbook for iPad

iAuthor, iTunes U, and the new iBooks is kind of what I've been waiting for.

I'm going to write a music theory textbook.  I understand that this isn't perfect, you can't create ePubs, you have to be in the Apple system, etc...

But I hope to create a book I can use in my class (and hopefully you can too).

My goal is to finish by the end of the school year.  What would you want to see in an iBook for theory?