How many do you need and do you need a reliable, long-term supply or are these custom one-offs?
If you can tolerate some uncertainty in supply chain, you might look to military surplus connectors and see what you can find in a surplus store. They're incredibly robust (as they're often in field conditions with GIs who could break an anvil) and often cheap to buy a box of them in surplus channels. Problem is, you won't be able to guarantee a supply of same in the future.