I've got three bodies, a 5d, 5d2, and a 7d - and have found dust, eventually, on all three's sensors. Annoying. The 5d classic wouldn't surrender its bits of grot to the only kit I had to clean things up, ad simple blower. Incidentally, said blower was fond of spitting out its delivery spout, as I've read some do. So I arrested that bad habit by strangling the engagement neck of the bulb with a small cable-tie pulled up really tight. The resulting compression on the spout locked it in place.
But the ongoing business of dust getting in was a big point of annoyance. I keep my kit clean and don't change lenses in places where dust could be foreseen as a risk. So I wondered how it was sometimes finding its way inside all three bodies. Dust generated by wear on the reflex or shutter mechs I could do nothing about. Then I realised that although my treatment of the bodies and lenses was bordering on obsessive, I hadn't been so careful with the body or lens caps. All I'd done with those was to engage them together and into a pocket in the big kitbag they went till needed. Then it struck me this was an excellent route for crap to find its way into mirror boxes and hence onto sensors. As the mirror flails up and down, it must create miniature hurricanes between the lens throat and the shutter/sensor - more than capable of blowing tiny dusty bits around on the caps' inner faces and if there is any static in the sensor itself, perhaps that might explain why some dust appeared to land on its surface and be resistant to puffer-blowing.
So I decided to wash-clean and air dry all sets of caps and keep them inside self seal bags. Did the same with the blower bulb too.
Too early to tell if this will do anything in the real world, but it can't hurt. It's one of those things that perhaps everyone else does and thinks it too obvious to mention? We'll see if it makes any difference.