I decided I wanted to mount a set of Swiss army surplus ammo bags to my rear rack for daily commute I'm my bike being built. I had seen them on etsy and eBay for 120-150. The ones for sale use bare metal hooks and a bungee cord.
I found an army surplus store online that sells the raw bags for 24.99
Turns out you can buy the "bontanger interchange transit w/ sway bar" as spare parts from trek online. I love this mount system. Probably wouldn't be great if your bags were carrying super heavy loads, but they're super quiet and hold bags super snug.
The bags have rigid leather on the top and bottom that work well for running bolts through.
All together the set was about $80 with a considerably better mounting system. A warning, they are not very big. While I am an IT person, I have recently thrown out my laptop and now use only an iPad. So my load for commuting is very light and small. For me, these bags are just fantastic, and will fit the new VO Polyvalent well, which should be completed next Friday