I keep on seeing a lot of eel-wrigglings with this topic. When asked if there's a relationship in between buying the meat (at least in today's marketplace), and others' intention of killing the animals, we only get the answer that they're not responsible.
They refuse to acknowledge (or disacknowledge) the relationship. I think that this kind of habit in eel-wriggling is not useful for the practice, as per the Brahmajala Sutta. I know that the sutta really has more to do with the question of whether or not there is a self... but I think it's still not a good habit.
There also seem to be a lot of inferences that are being drawn to the suttas (or commentaries)... making an attempt to show some kind of relationship (or the lack of it) between the eating of meat and the killing of the animals. I think that this kind of habit should also be discouraged. (See: AN 3.66
If we still must make some kind of inference, then I think it's a good idea to make sure that it's a wholesome one... i.e., that eating the meat being offered is meant to encourage generosity (which I think would be a blameless inference); not to show that it's OK for us to just allow others to continue the killing, nor to show that there is no relationship at all in between what one eats (especially when he procured what he ate) and the animals being killed. The latter two I think would be seen as unwholesome inferences, at least to a sane person... and I don't see what their usefulness might be at all to the practice. I think they might even be pernicious if the practitioner is unaware of what habits gave rise to these kind of inferences in the first place.
Ben, your suggestion about eating the deceased human remains seems like it might be a good idea on the surface (at least for those who feel like that they must continue to eat meat for the nutrient value)... but I even wouldn't suggest that to them, because of the prions. Most people are likely to gain some kind of serious degenerative disease from that... similar to the mad cow, which was what happened after the farmers fed their cows some ground-up leftover cow parts... as an attempt to save on the cost of feeding them grass, or even grains.
I think that a better suggestion would be to just get your meat from a dumpster, after the supermarket throws out the stuff that no one bought. This might even be a good practice, to study what kind of habits arise... and whether the person would think it's worth it to continue obtaining the meat in such a way, just to sustain himself... especially on a daily basis, considering other alternatives.