Not particularly for the great outdoors, but my PalmOne Zire72 does very nicely - cheap and with some good power. You can load an infinite number of programs on it - mine is music player, internet (through phone), organiser (of course), tv remote....etc etc.
You can, but only ebooks converted to plain text...
"iPod 2.0 software brings exciting new features to your iPod, including a Note Reader that displays text files that are stored in the Notes folder on the iPod.
The Note Reader also displays the folder hierarchy in the Notes folder, allowing you to organize your notes."
"The size of any single note is limited to 4kb, any text beyond 4kb is truncated.
The Note Reader supports up to a thousand notes"
The iPod is probably not as useful as a palm for use as a digital device out in the wild.
Another option would be for folks to check out ebay for the older Macintosh Newton 2000 - 2100 organiser (£80-120), for a unit which was discontinued nearly ten years ago these machines have an incredible amount of support on the web and theres always new software in development for them. Add to that the huge screen which can switch to landscape view and you will have a much better ebook reading experience.
However it's greatest asset for those heading in up country is up to a month of battery life from four AA cells!