Southpark:
Go to ebay and search for "3 pin outdoor connector".
Well I did say "after an extensive search". Of course I have found some similar on ebay and elsewhere. Very few were panel mount, none that were had panel mount sides this low profile, none had the panel mount side female, and none had as good quality as these.
So the way I see it, I'll eventually use a great many many of them, so 100 isn't a terrible MQO for a wholesale price. Especially if they are unique enough that you could resell some retail, and make it easier for other st get them.