Don't know if this has surfaced yet, but the uke is used nicely on "Isn't It Time" on the new Beach Boys album, That's why God Made The Radio. With such an emphasis on beach music, it really surprises me it hasn't been used more by them over the years. It's track 3 on the new album and here's a link to a recent live performance. Not sure who that is playing the uke on the right. Enjoy.
http://www.youtube.com/watch?v=EiBgzhteclQ
http://www.youtube.com/watch?v=EiBgzhteclQ