This is all excellent advice. I do expect that some percentage of schools will have e-book options this fall, and a much larger percentage will in the fall of 2013.
You could ask your school contacts point blank which of your courses will have e-book options this fall. They may not know at this point; students that ask may help them move in that direction. Keep asking, and make your decision as late as possible. Deferring decisions is part of the art of engineering.
At the same time, there's not a huge downside waiting a year in getting an iPad. Performance will be better next year -- especially if processor circuit size shrinks.