> I'm just trying to figure out the reality and practicality of >getting a D600 for the way I shoot.
I shot a couple thousand familiarization images through the camera on either non-important stuff or shallow DOF images where you'll never see dust in those sorts of shots. I did regular in-camera cleanings during this time. I even shot a 2 hour time-lapse with mine during this with the aperture at f/11 without any visible issues.
At the end of this, I cleaned sensor thoroughly and I expect the camera will be normal going forward as far as sensor cleaning goes - mine was not as bad as what others have seen, I suspect the early cameras might have been a bit worse on this issue.
"Extraordinary claims require extraordinary proof " - Carl Sagan