If it was just for the simplest things, like fixing a blown seam or adding reinforcements, I might suggest tent and outdoor awning places, or shoe and boot repair places.
However, I think the other poster is right--you are going to be shocked and disappointed at the prices charged for customized tactical gear. I don't blame the businesses of course, they have to put the machines and the workers to the most profitable and consistent use, so slow and non-standard custom jobs just doesn't make a lot of sense, outside having idle capacity that can absorb the relatively inefficient custom jobs.
However, the shoe or awning places might still be a place to ask around for the machines themselves. Maybe someone has an extra in need of repair, or they know someone who got out of the business. After that I would try ebay.