I've just defended a settlement from Raiders and one of them was of "Legendary" status.
After dealing with them all, I was anxious to get to the body of the Legendary Raider to loot him but, unfortunately, couldn't find his body anywhere.
A great suggestion for Bethesda is to, perhaps, create an additional piece of code which allows you to order a settler to loot the bodies of the fallen which can instantly bring up a loot window containing all items from fallen enemies.
This would be a little more realistic rather than hunting around all over the place for individual bodies and, sometimes, not finding them!