Do you care about weight? I mean, you're hauling Emperor cabs around, so probably no.
Throw some EVM-12Ls in there
If you don't like the idea of a 160 lb cab, Wizards sound like they might be up your alley, although that's still a pretty high-powered cab. A lot of doom sounds involve low-wattage speakers breaking up, so in combination with your high-headroom Emperor it might be nice to have something that is a little less "clean."