Or you go for the Markbass 102 combo?
I use the same rig as you ... just recently I was pushed into using the 121 combo on its own. I was amazed how focussed, and loud it was, even without the extension.
It probably moved less air overall, obviously, but in a small, packed venue, it was really easily loud enough for backing standard harp/guitar/drums blues combo ... probably never got above 50% vol... great sound
It is not a 'cello my dear
1937 King Mortone, Lamberts Deluxe; 1938 Kay M-2, Guts/PsychoSlaps; 1968 B+H Excelsior, Guts/SilverSlaps