Unfortunately, most of my cameras are sandbox cameras. The Speed is not, as it is super clean, but pretty much everything else is. Even the Sinar has gone out and about quite often. It rode shotgun in my passenger seat, on a tripod, for a six-month project I recently shot. It took a lot of beating, and kept on ticking.
The cameras that I purposefully take if I seriously fear damage, theft, or loss are my AE-1 Programs, my Electro 35, or my Powershot if a point and shoot will do the job. I also view my 10D as one of these, however, I don't use it as such because my only lens for it now is the 50mm f/1.2.
The camera I take when I need the toughest camera in existence is the Nikonos V. This is my number one hiking and climbing camera...and it shows it now.