I just redid the trigger wires on a larger Metolius. I went to Tacoma Screw, got good cable cutters, cable, swages and a swaging tool. It was about $60 for the whole thing. It was a little tricky, but the wire and swages are pretty cheap, and I got it on the third try.
They work great!
Wouldn't some sewing services have a bar-tacker? Conceivably, you could provide materials and specs...