I would recommend using a Solid State drive. No moving parts = no vulnerability to shocks (at least not the drive). Go to TigerDirect.com and do a search on "solid state". You'll get plenty of hits and you can read more from there.
A more complete solution would be a "mobile" or "auto" PC...
Hmmm. I step into these waters a bit hesitantly. I usually just sit back and read. But this one I have to jump in on.
From the perspective of an ex-Microsoft engineer that has converted completely to MAC after leaving the company 3 years ago and removing the "horse blinders" from my head...