i think may be possible if you change loftemp on unit armor to be [ x , x ,x , x] or [x , x]
so when you mount a big armor it will look like a big ass unit. however will glitch the shit out of it or nothing will happen. i don't think the engine is prepared to do it. you want me to try it? i did it before changing loftemp on unit to make them invisible and works. technically speaking armors are unit graphics so whatever you can do on any unit you can do on armors that soldiers wear.
will glitch out cause the space the soldier takes is 1 in the craft. but if you have 10 ppl all wearing same armor they all gonna be inside each other being bigger than normal. you won't be able to make them take hwp spaces. also what happens if you crouch or use special strafing or open doors. will confuse the engine. or not. dunno
another way you could do it is kill soldiers to make hwp out of them. make a special hwp that costs 1 soldier+credits to create.