SOG is an American brand, but the ToolClips and Micros were made in Japan. Many Spydercos are made in Japan as well, but like you said, they are also a US brand.
Kershaw is a silly one- Kai is a Japanese brand, but Kershaw is a US brand that sells Kai knives under it's own name in the US and other Western countries. Kershaw is owned by Kai, so I don't know if that qualifies as a US brand or a Japanese brand or what!
I am certain there are some Japanese multitools out there, but they may not be exported like many things in Japan so we don't know much if anything about them.
Def