I'd nearly agree with Hypothesis on this one - surely ya can't be expecting to lug about a laptop in the conditions.
If you do need to record data, why not get either
a. A PDA with voice recognition software - most of them have some form of Windows software that can be then t/ferred to the main PC/laptop back at base
b. A good digital dictaphone - the one I have at present is ace and simple to use
If you use either in conjunction with some formalised means of recording the data, I'd reckon you'd be sorted. I also think that regardless of location, a laptop would would be too cumbersome, especially if doing interview.
If you still need a laptop out in the field, the supervisor has a tiny Asus which utilises OS software and seems robust enough (I think, and I could be corrected here, it runs using the Linux Op. System, which has become more user friendly). It is extremely small but seems to do the job. You may want to get protective covering regardless of what one you choose.