Don't know much about a 5d but my 7d is pretty tough although not near the 1ds3.i dropped that onto a concrete floor twice, rocks twice, just been out in a rain storm so heavy the camera looked like it had been in a bucket of water. Worked perfect. The 7d has been in mud at a racetrack and also fell onto a tarmack road, worked perfectly. Had a new 70-200 out in a monsoon, it was drenched, worked perfect.
All in all, pro gear best but 5d, 7d and l lenses are far tougher than you think.