I wouldn't go as far to say SS and the Expendables are reggae.  More reggae-inspired So-cal rock. But whatever, they're top on my list. Listen to Mystic Roots, Dub Congress, Pepper, Long Beach Dub Allstars/Short Bus if thats what your looking for. As for Reggae: Cocoa Tea, Lutan Fyah, Gyptian, Capleton, Sizzla, Barrington Levy,  All the Marleys, Lyricson, Gregory Isaacs, Cali P..... the list goes on.