Used to have a FP Monarch. Same issues with carrying around such a monstrosity plus a laptop (I work in the field as well).
Didn't want to get a PDA and learn Grafitti so I bought a Handspring Treo 90. Uses thumb-keyboard, no Grafitti necessary! Small footprint, so re-size fonts to largest setting. (IMO, the new Sony PDA w/keyboard is nicer, and has a large screen, but I was not willing to fork over the $500 at the time...you may want to consider those also)...There are a few models out now that do not require that you learn Grafitti...I haven't and don't plan to.
Also use a voice recorder for gathering thoughts, etc. in the car or elsewhere in the field.
And never underestimate the power of the legal pad for capturing information...I still use one for quick notes, etc. and toss into an inbox for processing later.
It would be quite the challenge to go totally 'paperless'. A combination of the three tools (PDA, legal pad, voice recorder) works well for me, and takes up much less travel space-very important when you consider that laptops are the equivalent of 'bricks' that are being lugged around all day.
Really, all of this comes down to managing lists, as has been said many times before here. Use the best tools for *your* needs and you can't go wrong.