Why not get a semi rugged laptop and a pelican laptop case? They are far more rugged than a panasonic toughbook and you can get anything you like, toughbooks are way behind the curve at the highend and really expensive. You can also remove it from the case when at home so you don't have to sit with a huge brick on your lap.
If you are breaking them while they are in use then this solution may not be for you as the case is obviously open while its in use, but, even when open it has good impact protection but you may be vunerable to water. They have heavier foam than a regular pelican and it fits the lap top as tight as you like, allowing for ventilation. It has little tabs that hold the laptop in should you drop it while it is open.
When its closed your laptop is pretty safe, you can drive over them, throw them in water (they float) and they are completely protected from dust. The auto parking hard disks in toughbooks are nothing special and can be found in Fry's and multiple vendors online.
I guess it really depends on what you are doing with it.
