Get a vest and do it yourself.
Using this picture, scale it so the blue square on the box is 1"x1".
View attachment 1481292
This will give you a measurement of about 3.25" from just above the rivets down to the bend.
The bend is in the range of just over 1/8" to fit the D ring, then back up another 1".
Top of strip is about 1.5" and tip is 1/4".
Rivet washer is 1/2", rivet head about 5/16"
Center of rivets is 3/4" apart.
You just need 2 strips at around 4.5"x1.5", 4 rivets and 8 washers.
Basic tools needed:
For cutting, hacksaw or Dremel w/ cutting wheel.
File or Dremel w/ grinding bit.
Sand paper for smoothing out the edges.
Needle nose pliers for the bends.
Drill or Dremel for the holes.
Rivet gun.
Exacto knife for making the openings in the vest.
Time depending on tools used around 1/2 hour.