550 Paracord Sling. Its not a DIY but it's also not that expensive and if you are already handy with knots and paracord, you could make this by studying the patterns.
paracord projects | Paracord project - a set on Flickr
How to tie Paracord knots to your backpacks >>> Great DIY how to with photos for all the different steps to make the knots
Paracord Zipper-Pull with Diamond Knot - Survival Colorful Luggage Identity Zipper Assist via Etsy
Solid Black Heavy Duty 550 Paracord Survival Lanyard by c2zinn, $16.00