How can I make sure a shed is hurricane rated?
I can think of two options that should work...

Shipping Container

A steel shipping container should be more than strong enough to meet hurricane ratings, and come in just about any size.



This company sells anchors that it claims should withstand strong winds &amp; hurricanes, though they "have not been scientifically tested." They're basically big triangles of metal or long screws driven into the ground:



Monolithic Dome (shed sized)

A dome constructed of rebar, foam &amp; concrete/shotcrete. They're very very resistant to winds (probably tornadoes too), and the weight combined with a cement slab &amp; footing should make sure the whole thing won't blow away, ever. See Wikipedia or Inhabitat.com



Alibaba has a larger one, with images too:





For more conventional construction, if your neighbourhood/city has hurricane requirements then they must have guidelines on how to meet them, especially for usually DIY-friendly sheds. Check with them first.