Great article hawkaw!
SwordofJah: I would say that no, a blood transfusion is not consuming blood. Something that is consumed or eaten goes into the stomach to feed or nourish the body. A blood transfusion is a "transplantation" of a fluid tissue. Also, the comparison of the twins to a blood salvage "closed circuit" is not really correct. A blood salvage does not involve the passing of blood from one human body to another human body. A better comparison might be the direct transfusion of blood from one human to another. For instance if the twins had grown up and one of them required a transfusion and the other twin provided it for him, why would Jehovah forbid this, considering he allowed it in the womb?
I would agree with you eyeslice that the command was out of respect for the animals life, as their blood was the "symbol of that life". There was a good quote that read something like "does it make sense that God would want us to put the symbol of life above life itself". In other words out of respect for the life of the person who gave the blood (even though they are still alive - unlike the poor animal in Genesis) would God really expect us to forfeit our life or the life of a loved one?
Artful