People also need to take into consideration that many of the bodies will never be found - the same was the case with the tsunami - the tidal surge comes in and then goes out taking many of the bodies with it.
Well, there are any number of angles from which we can view the problem.
But I look at it this way: we've rescued 38,000 people and rescue operations are still going on. So what about all the people who couldn't get up high enough and drowned in their house? How many people have died from thirst up in their attics? How many sick people died from heat exhaustion or lack of medical care? It's already been eight days.
120,000 people in New Orleans did not have personal transportation. Add to that the people who did have cars but chose to stay. Say 200,000 people stayed in New Orleans. 40,000 have been rescued. Another 60,000 were taken out of the Superdome and Convention Center.
Then you have to add in the dead from outlying parishes and Mississippi.
I think that 40,000 is a working estimate, but as you said, it's a conservative one. People need to be ready to see it go much higher.