Here is a lead I found. They are typically toys sold in Japanese model shops. I see them all the time when I am in Tokyo. They are plastic or die cast, and usually part of a series. Here is a Kate.
I search Japanese shops and retailers. I found several Tamiya 1/100 SeaKings for less than 10 bucks, and then fully made and highly detailed ones by DeAgostini Japan (way better than the old plastic kit) for not much more.
I the search terms were 1/100 Nakajima Diecast. Look at the images and follow the various paths.