With help from Bruce Whitten, I located some sources for the material, which is called Shock Gum.
Lines End does not have the product, but maybe Byard can order it. 15' spool of the shock gum material in 9# and 15# strengths marketed by Rio http://tinyurl.com/y95pwc Completely assembled shock gum section with loops on both ends http://feather-craft.com/2006MAster/fcpage.asp?page=22 Wes Wada Bend, Oregon
