Jake. Of Course
If you've never heard Taimane Gardner you need to. Virtuoso playing and a super nice person.
Raiatea Helm. Beautiful voice, old school. And Jazz...
The incomparable Ukulele Orchestra of Great Britain
Pablo Requena is a fine guitarrero from Spain, now in the UK. Very helpful guy.
Robert Kurosu of Kotaro Guitars makes very fine ukulele and guitars
Jungtae Kim and family make interesting ukulele in Korea. Check them out.
Eric Devine on Maui makes beautiful ukulele and guitars.
Hermann Hauser III. A member of the great guitar building family, he's had some helpful insights.