HIPPA/SOX: Lots of hosting centers deal with security requirements by building a chain link fence around an area. It works, but it's not efficent, not that expandable, and arguably less secure since you can see in. Moving/consolidating racks as you grow gets hard.

However I could see that once you were of a certain size, you could rent an entire container for our equipment. Then you can secure that however you need. Motion sensors to prevent movement, independent alarms, etc.