Needham's stuff really is the bomb when it comes to large-scale studio cabs. But the God Of All Eurorack Cabs has to be something from the crazed Canadians at EMC: https://eurorackmodularcase.com/ ADDAC System also has some enormous cabs that sport 197 hp widths as well as beefy AF power to match, plus you can get a dual 19" rack "topper" with 2 to 5U of space per rack.
The real solution, however, is to just turn all of the walls in your studio into a cab...