Carbon tubing, epoxy (west), and make the top hold yourself with wood (laminate) and the west. I think I remember seeing the tubing on Titanium Goat (may not be the right size) or could possibly source elsewhere or Bending Branches. The toggles could most likely be found at a decent hardware store or MacMaster-Carr. An archery shop that sells arrow shafting to make carbon arrows could cut the shafting for you.