You don't have to work in extreme environments to want a laptop case that can take a serious beating. This DIY project will protect your expensive laptop and also provide more juice for it.
Jason Fox built this military-spec case to accommodate a MacBook Air. If you have a different laptop, you should be able to follow the instructions and just adjust for your laptop size. You'll need a soldering iron and some other common tools, as well as a Pelican Hardcase, Hyperjuice battery pack and various supplies. After completing the project, you should end up with a battery-charging case that fits these requirements:
Can be away from a power outlet for at least 24 hours with no change in computer usage behaviour.
The computer is secure while in the case.
All cables, batteries and accessories can fit into a small case (17 inches x 13 inches)
The whole package should be shockproof, waterproof and resistant to temperature swings.
Hit up the link below for the step-by-step instructions.
Building a Military Spec MacBook Air Case with Long Life Battery [Never Stop Building]