The buckle: As discussed in
this other thread I wrote trying to identify the buckle, I don't know what they used for the buckle. It is similar to buckles make by Cobra, Raptor, and Stubai. Also, if you look at buckles on Tower Harnesses, they are all this "quick connect" style. Additionally, there are a couple cheap knockoff Chinese brands of quick release buckle. So far, all of them are too different to have even been easily modified to be the buckle in the movie.
View attachment 362435
That little lip under the side release latch is something I have not seen on any other quick release buckle so far. The best guess so far is that is is an old version of a buckle that used to be sold but is no longer available. If anyone can find something that could work, please share
Failing that, user
Kevin Gossett seems to be considering making non-functional copies of the buckle, since it doesn't need to work for a bag like this. I have been experimenting with designs for a functional buckle which I'll be building this weekend.