Kerr Interiors demountable partitions are the answer if you need an easily mobile and reusable wall system.
Light Gauge Floor and Roof Systems
Light gauge steel stud roof systems meet fire code, are typically light weight, and have very short delivery times as the materials are readily available
There are several options for Floor systems as well, ranging from Cold Formed Steel floor joists with thin deck and concrete to Ultrabond or ComSlab decks with concrete. All give excellent fire ratings and sound ratings (typically an STC of 60 can easily be achieved)