e-Textbook Open Standard

One thing that I think many of us are interested in is the concept of an open standard for the e-textbook.  It is clear (at least from the brief web search that I have made) that the epub standard is not going to help us create a compelling
e-textbook.

Why would students (or faculty for that matter) be interested in using something that is just a digitized version of what is in print (besides saving on chiropractic bills)?  Being able to use the iPad, HP’s Slate or any number of other new mobile devices, we should be harnessing the multimedia capabilities
of these devices to create something that goes far beyond the e-reader/e-book.  This new standard would allow us as
faculty and mobile innovators to create what is needed for our future students.

I would propose that we develop an open standard that creates the e-Textbook of the future.

Such a standard should:

        ·      build upon the ePub standard

       ·      allow for multimedia (mp3, mp4, flash, etc)

This is just a preliminary list to get the ball rolling.  Please, give me your feedback, add to, delete, and improve upon this starting point!

*** Please, if someone else has already started such a project somewhere else, let me know!  I’m not interested in re-creating the wheel, but my searches have found
no such open-standard.