Pretty much any modern laptop screen should be OK so long as you get the matte type and not the glossy ones (like truebright, crystalview, etc). Some of the older (like pre P3) screens that were not active really would bite in the sunlight, but you won't find thse anymore.
Toughbooks would be good if you're gonna be exposing it to a lot of humidity and dirt and all.
More exactly hw much battery life are you looking for and how portable do you want it to be (i.s. what size)?