I actually saw Sabbath without out Ozzy, in fact Dio was their lead
singer, and they did a song called "Trashed" from the 1983 LP "BORN AGAIN", it
was pretty rockin', sounded more like a "Machine Head" era Deep Purple, than
the classic SAB's sound. 

Not sure if it was the smoke, but it was Ian Gillan, from Deep Purple who sang on the Born Again album/tour.  I saw them open for Judas Priest! in '83!
Dio sang on Heaven And Hell, Mob Rules, and the live album from around then.  Dio did sing a mean "War Pigs", though.
later, joe
jtgimplosion.com