According to http://ja.wikipedia.org/wiki/%E3%83%9E%E3%82%A4%E3%83%86%E3%82%A3%E3%83%BB%E3%82%AA%E3%83%BC%E3%83%9C%E3%83%83%E3%83%84 , Mighty Orbots was re-broadcast in Japan on Animax (a basic cable/satellite channel), although it looks like Animax took down their page for it that's linked in the article.

Have you tried looking for it on Japanese P2P? Digital recordings from the re-airings would probably look better.

Perhaps a DVD release might also be released in Japan someday, or a non-upscaled Blu-ray if we're really lucky.