I actually think that they (Apple) will come out with something soon.
iTunes has already shown itself to be well setup to distribute media to consumers. And I've heard of some people hacking iPods to display text files. It would be very easy for them to add ebooks to their lineup. It's really the only thing missing from a consumer-media point of view. They have music, movies, television, radio (podcasts).
I think it would be a pretty good device.
However, that being said, I think that what ali said is also true. Apple hardware is usually more expensive than the competition. I'd guess a price of around $800US.
But given the choice between an iliad and some "prediction-ware" device from Apple, there's only one
choice.