As much as I hate to turn anyone off e-ink, there is another possibility. (But if you want to read comfortably in the sun, it doesn't sound like anything can compare with e-ink.)
Anyway, what I'm suggesting is that small form tablet pc might be an alternative. You said you are using a notebook right now. In response to my
"dream tablet" specs, James Kendrick at JkOnTheRun.com) told me about the Fujitsu P1510D which is a tablet convertible, so it can also a notebook. But it would work like a slate also, which may make it a lot easier to read from. It would be portable like a Franklin Planner size, satisfy any laptop needs you have, and it would have full windows capabilities, so you could do all that the regular Adobe Reader can do with pdfs like zoom, as well as run programs to read and convert just about any non-DRMd format you want.
Basically it could do whatever you do with your notebook now, and you wouldn't have the two second page turn delays, or slow document search times. Those are no big deal if you are mostly reading, but would seem to be a problem if you are mostly jumping around a lot in a large document while you are looking for the little bit of the document that you actually want to read.
It has an optional 6 cell battery that apparently would give you something like 5-6-7-8 hours life which might last you through the day. Plus 60 gig hard drive.
The main problem for any non e-ink device is that it would likely be hard to read in direct sunlight.
The secondary limitation is that it might be more like $1200-$1500 by the time you get what you need with the extended battery, case, etc.
Along the same lines, UMPC might be a slightly cheaper and much more portable option... like the
Samsung Q1.
This is just a thought for a different kind of alternative. But it won't give you a display anything like the awesome e-ink descriptions we've been hearing about!