Yeah, you are right, but to pick up on something you touched on... Additional structure needs to be added to do the job if that removed... The bulk heads act as a shear panel which is very efficient and lightweight... This can of course be replaced by something lower down and more beefy.. It's like turning a coupe into a cabriolet, the cabriolets often suffer reduced body stiffness a a result of removing the roof - a shear panel...
I'm not saying it can't be done, just that more work and calcs are needed rather than just firing up ones angle grinder!