Interesting points... if a device like the Apple tablet you describe comes out, it won't look anything like the mock-ups... It's going to weigh 2-4 times as much as a Kindle DX to get that kind of battery life, and it's going to be a lot bulkier -- none of those netbooks are less than 0.4" thick. And the iPhone OS may reduce power consumption demands somewhat, but the iPhone itself is nowhere near being able to be used for something like book reading for many hours a day -- the iPhone Kindle app burns a fair amount of battery life.
Color does seem to be an issue for textbooks... also apparently they don't have a deal with McGraw-Hill.
I'm not worried about weight. I don't look at it as a comparison to the Kindle but to carrying around 20-25 lbs. of books on your back during the course of a day.
As for the battery life, it will be an issue no question. But if a EEE PC 1000HD manages to get 9.5 hours (running XP no less) I'm sure that Apple can manage to push 11-12 hrs. with the far more lightweight iPhone OS. It will never approach the Kindle it terms of battery life, but it can potentially be the only item that you need to carry unlike the Kindle. Besides, on a college campus, you are never too far away from a battery outlet.