replacing drywall with dry things

6.2: gear/drywall/sand & metal:
. cheap fireproof and wetproof drywall could be done by
metal sheet panels bent and crimped in the shape of drywall,
then filled with baked sand;
or when used as panels on the ceiling,
filled with something lighter like perlite .
. not as easily cut into odd shapes like drywall is ..
. pieces would have to be prefab'd per architecture req's .