I'm not one of the Downloads Sentries so I'm not an expert on how they've handled these questions in the past, but I think it'd be better to put all requests in Asian Music Downloads and not in General Music Chat.
If it hasn't been commercially released in the US it's okay, that's why things like unreleased Madonna tracks or British/French/etc. music have been uploaded. I seem to remember someone uploading Tatu's Russian albums before, same thing for them. If someone like Beyonce has a Japan-only bonus track, I'd imagine that can be shared too.
You could use
RIAA Radar to try to find out whether the album/song you want has been released in the US.