If so where do you find the parts to make it? I have gone to Home Depot and Lowes but just cannot find the right material.
3.1.6 A hiking strap making one traverse of the cockpit may be installed. The strap may be padded for comfort with any material and shock cords may be used in the attachment system.
It does not exclude rope, grommets, the "hiking strap attachment device", etc.
This strap, and others of similar design are legal. Often doors are left open in the rules for innovation and minor experimentation.
When development forced the teardown of a wood aircraft hanger nearby, I retrieved a piece of NOS shock cord from the trash bin. It's not quite ½" in diameter, but stretches less than rope!"...The rules are pretty vague. They say you can use shock cords in the attachment system, but they don't even say anything about rope...!!