I bet there are some custom made backpacks somewhere for the rich, 45 year old 3.0 woman tennis players at my club, but it would be way cool to make a custom bag. The only problem i can think of is it would probably be less durable than a mass-produced one because any manufacturer probably has made 500,000 more bags than you. I would try if I had both time and money to throw away.
2x AG200 13.6 oz Blue Gear/Isospeed Baseline Spin
1x MW200g, 1x Mfil200g