[xefyr]

Because it hasn't yet been mentioned, you might consider an OLPC. They're small screen size is, imo, greatly compensated for by their durability, portability, and mobility. They run debian and can be used in direct sunlight. Did I mention the price is right? Oh, they also have much better antennae than the thinkpad. :D

I'm not sure if the needs you outlined above are driven by some technical requirement or if that's just a list of the laptop-de-jour to which you are aspiring.

If nothing else, check out the hardware specs for the pure geeky pleasure: http://www.laptop.org