I ran across these straps in the local Ikea. http://www.ikea.com/us/en/catalog/products/25989100
11.5' long, 100% polyester, the small clasp buckle can be cut off and a loop sewn.
I don't know how much they weigh(no scale), but they seem light to me. Rated for 882lbs. One package could give you 4- 5.5+' tree huggers for $3.99. I used them on my last trip and had no problems. 6'2 218lb.
Thanks for putting the list together. I was never involved in scouts at any level, but am considering joining as an assistant leader/helper, whatever is it called. There is a group that meets at a nearby church according to the sign.
have a good'un