A-WALL Building Systems, one of the originators of the "modular office" concept, offers everything from a simple 2-wall receiving supervisors office to complete one or two story "clean room" facility for your warehouse or office area.
The modular concept allows quick installation, the ability to relocate within your facility or move to another location without a lot of effort. Since these structures are "mobile" you may see quicker depreciation than with stick-built construction.