I thought you were talking to me since I'm the one that mention e-books.
I do agree that e-book readers are light and very efficient. The thing is, I use scanned books books. I have for years. I'm a tabletpc user. Nothing beats a scanned book unless you can possibly get an unlocked pdf version from the publisher, which is basically never done, at least not legally.
Scanning a book means that I can digitally read any book I can physically get my hands on. It's simply not possible to get "true text and line art" versions of books of many books on e-book readers right now, and possibly ever. This is not a restriction for me whatsoever. I certainly don't have to buy books twice either. The book will look exactly the same on screen as it does in hand, at least down to 300 dpi. Because I will be using it on a tabletpc, I can search, highlight and annotate.
The thing I envy about e-book readers is that the black & white versions look great in bright light and have spectacular battery life. That's not really a factor for my trip though. If I get a u820 with gps, then I'll only turn it on during bright hours to locate myself...that is, if I don't bring a handheld gps, and if my compass/map navigation skills fail me. Most times I'll be using it at night or in the early morning to plan my hike for the next day, and hopefully to get a little studying done so I don't lose too much ground while I'm out.
The trip I'm looking at is the PCT. Carrying spare batteries, or external battery packs, creates its own problems. It's more weight, has to be charged sequentially or have another charging cord, depending if it's an internal or external battery, respectively.
When I mentioned bulk, I meant that it would be a smartphone (5.6 oz for Blackberry), plus it's charger, an e-book reader (10.2 oz for Kindle 2), plus its charger, an advanced gps (7.5 oz for Garmin 60CSx), plus its charger, and a bunch of spare batteries. Add the weight of the devices, plus chargers and spare batteries, and that could easily be over 2 lbs. The Fujitsu u820 is about 1.5 lbs with the extended battery. I estimate 1/2 lb for the charger. That puts it about even with the other devices. I don't care to pull up the specs for sizes right now, but the u820 is very small, very coat pocketable.
Here's the thing though--reading e-books is the primary goal. I need to be able to read scanned books that I created in full screen mode, in color. If the computer replaces other hardware, great, but that's not enough to sway my decision one way or another.
Find me an e-book reader with the resolution and processor to handle displaying color ebooks scanned at 300 dpi that I create myself and I'll give it a look. Storage may be an issue though. Scanned guide books are roughly 300 megs each, but three of the textbooks I'll be bringing are 2 gigs combined.