1. Go to www.carryology.com
and browse the in-depth articles on the site. There are numerous articles about craftspeople designing and making bags the way they wanted.
2. Select a maker you like and contact them.
3. Ask them to make your desired bag.
Learn how to make your own bags. Market them effectively and wait for the hipster-tennis gearheads to come to you.
Build a better mousetrap and the world will come knocking on your door, etc etc.