A friend and I were discussing second hand toughbooks that one can get on ebay yesterday. These are mil-spec laptops made of a magnesium alloy, with rubber gaskets/covers on all the ports. You're supposed to be able to drop them, submerge them, and all sorts of abuse, and they'll survive. The screens are not that expensive to replace either, if they break. Sometimes you'll get a laptop and the screen is twice as expensive as another used complete machine of the same model. You can get a used toughbook for around $200-300, perhaps missing the hard drive or the CD-Rom drive, or perhaps complete.
The big thing if you're trying to save money is to make sure they have the hard drive caddy in them. They are also kind of complicated on the inside, so maybe it shouldn't be the first laptop you ever try to disassemble.
But it just occurred to me, if these are military surplus or something, wouldn't they have that Chinese spy chip in them? It's worth looking into.
The other question is, if it's the spy chip, can the chip be flashed like a BIOS chip, and de-Chinafied?