I guess the winner for me is...
Kim Mitchell 15 times(once with Max Webster)
Kiss 9 times
Forgotten Rebels 8 times
Joan Jett 6 times
AC/DC 5 times(3 w/ Bon scott)
Blue Oyster Cult 5 times
Nugent 5 times
Cheap Trick 4 times
Peter Noone(Herman's Hermits) 4 times
Iron Maiden 4 times
& a bunch of 2 or 3 timers including Heart,Aerosmith,Cinderella,Van Halen,Molly Hatchet, Rush,Frank Marino, Sabbath,Ratt,NY Dolls,Blackfoot,Neil Young,Whitesnake,Faster Pussycat,Alice Cooper,Ace Frehley,Motorhead,Motley Crue & many more