We started a little late so the "scavenging" didn’t really take place and instead we ended up purchasing a good deal of the items used to construct this headless costume.
We started with a basic set of football shoulder pads and we modified them (cut off the portion of the padding that wasn’t needed for our costume) from there we re-configured the top portion of the pads to act as a cradle. Then we went to our local fabric shop and purchased a solid block of firm foam rubber which we went on to cut, shape and fit into our "cradle".
As the shape started to come to life we fitted our daughter into the shoulder pads and marked the foam rubber for more cutting and shaping. We attached the foam rubber to the cradle with zip ties. Once we had our shape nailed down we found an old flannel shirt (sadly one of my favorites) and proceeded to fit it around the foam rubber.
We used news paper to stuff the arms and safety pinned it into place on the chest of the shirt. Then we used more safety pins to attached the stuffed gloves onto the end of the arms. We used over sized sweatpants to pull up extra high and had our daughter place her arms into the sides of the pants to fill them out and complete the effect.
My wife with her vast special effects experience (lol) started in with the dead makeup and fake blood around the "stump". As we visited neighbors throughout our community we continually complimented on "the best headless costume we've seen all night." The effort that went into this costume was well worth the end result and the time together our family spent making it sure beats a quick stop at a local store for an off the shelf costume.