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Not being super familiar with some those, it will depend on what the f/2.8 sensor in the 40D reverts to with slower lenses. Does it remain a cross sensor, but without the extra precision of the f/2.8 feature, or does it revert to a non-cross type sensor? According to DP Review, it seems to revert to an f/5.6 cross-type sensor, inline with its other AF points. The 1000D has only a single, central AF cross-type sensor. The others are non-cross, meaning they'll be less reliable with your slower lenses with lower contrast subject matter than the 40D. Considering both are 10MP cameras, you're likely to get a better user experience from the 40D. And likewise, if you compare the 1DIII vs. the 40D, it's going to be a much faster feeling camera, though AF with slower lenses might not be a noticeable difference.
But in general, I don't think you can look at only the type of AF points available. The software in each camera is going to be a factor, as well as the processor(s). Some of the higher-end cameras have more than one processor, where one might be specifically dedicated to AF, or camera functions, while the other deals with image processing, etc. Generally the more expensive the camera, the better the AF and overall performance will be. However, if the camera has many AF points that lose cross-sensor sensitivity with slower lenses, you might actually get a more positive AF experience from a camera that maintains f/5.6 cross-sensor sensitivity. Cameras like the 1D series are squarely aimed at high-end users who demand the highest performance and have the lenses to match. it's really a matter of deciding which features are most important to you.