Levon Helm of The Band. And Jellyfish's lead singer (whose name escapes me) was also the drummer. And I remember a metal band called Exciter (who I saw supporting the mighty Judas Priest in '83) had a singing drummer. Bloody awful they were too.
The Most Reverent Keith Moon!{ he sang on every album!}
Dave Clark {of the Five}
Stan Poole{Dave Dee, Dozy,Beak,Mick&Titch}
That guy from the Worzles!
Ginger Baker
Dave Swarbeck{Amsterdam Lil}