Comment Re:Standalone GPS (Score 3, Insightful) 300
Waterproof up to one meter, and it floats so no worries about loosing it in the water. Also shock resistant and crush resistant. I bought it many years ago for the palm I've used then, and I was happy to see that the N800 was also usable in it. I hope the N900 is as well since I plan on getting one at some point, but it should be, since its about the same size.
I use my N800 as a GPS outside sometimes, and use this so I don't have to worry about dropping it in a moist terrain or if it starts raining. I also use it for reading ebooks when taking a bath.
So a smartphone/pda doesn't have to be unusable in conditions like the ones you describe. Altough I'm not sure if you could make phonecalls while its inside the shield, it might block the sound waves too much. Touchscreen devices work great on it, since one side has a soft transparent plastic film over where the screen is. Buttons on the front work well trough it too. Buttons on the side or top are not reachable however.
I did some tests with mine, among other things leaving it at the bottom of my bathtub for 24 hours with something heavy on it to make it stay at the bottom. No moisture got in.
So pdas/smartphones aren't necceserily useless in the conditions you describe, you just have to have the right gear for it.