Maybe not 10, but my company (in the US) has relationships with several machine shops nearby (some within walking distance of our office) that do custom metal f

Maybe not 10, but my company (in the US) has relationships with several machine shops nearby (some within walking distance of our office) that do custom metal fabrication for us, and sendcutsend and xometry can handle more exotic stuff without having to ship it from Shenzhen. I think the bigger advantage of Shenzen is more for actually manufacturing at production volumes cheaply, although maybe if you need something really exotic? Custom metal fabrication is not a good example here, I have a neighbor who runs a custom CNC parts business out of his garage (said garage is largely taken up by his CNC mill).