There is some research going on the UK (I can't remember the University now) to do with printing buildings. The potential for reducing raw material and labour costs must be huge.
I have a Kindle and iPad and use them for different things, I found the iPad isn't very good for book reading, it's too heavy, too bright and the battery life isn't good enough. On the other hand I can read from the kindle just like I would read from a paperback.
The only thing I would like to see from Amazon is a larger display version that is suitable for technical books.