my grandpa still has some trench art that my great grandpa made during WWII. both of them were in the marines in the pacific, but grandpa only being 18, he was on the front line. great grandpa re-enlisted & was a paper pusher seein how he was in his 40's by then, so he had the time to do stuff like that.
the pieces that i've seen that he made were a butter knife & spoon out of a couple 30-06 shells, one complete one for the handle & one shell hammered flat for the knife or spoon part. he also has an ashtray similar to the one in the background of your vid, only it had 3 half shells brazed on for cigarette holders, & a beautiful P-38 Lightning scale model made out of rifle shells & using what i think was a .50 round as a stand
i'd asked my grandpa about them a few years ago & he told me that his dad made a bunch of that stuff when he could & sold it to whoever would buy it, then usually sent the extra money home to his wife....who i'm sure could've used it since her husband & 2 out of her 3 kids were on the other side of the world.
there must've been so many people making these things, because on ebay i've seen pieces similar to the ones my grandpa owns and no 2 of any design are the same, plus they come from all over the world. makes a guy wonder if they had patterns for these things in Stars & Stripes or something