These four gents are not strictly ukulele, but they do incorporate them.
Their latest ablum, "Ukulele Kuricorder", employs ukes liberally as one might expect.For samples, try the web page of their recording company, Geneon Entertainment.
Their music will probably sound fairly "novelty" to most Western listeners.Eine Kleine Nacht Musik, Darth Vader's Theme, Power to the People, and Bohemian Rapsody all performed with recorders and ukuleles no doubt go a long way to boosting that impression.They definitely are in their own orbit.
Being their most recent album suggests there have been others. Indeed, they have put in appearances on several of the Rolling Coconut-type omnibus albums like "Ukulele Star Wars" and "Ukulele Lennon". Additionally, their music has been featured in the movie "Quill". They also perform the music for a children's TV show, "Pythagoras Switch", on NHK. Their complete discography is available in Japanese on their web site.