I love these house plans but it looks expensive to build. I'm not sure how to get the rounded areas in the framing.
The link also has publications regarding safe rooms. I've considered using one instead of a basement for our tornadoes here in Michigan.
Helpful set of links regardless!
http://www.bluesky-foundation.net/index.php/publications
In your wandering through the search engines, you have noticed that Monolithic Domestm believes that with one of their houses you have a safe house :) instead of a safe room :'( . You'd still want to be away from the windows. I don't hate Monolithic Domes, but I do think that some of this is a bit overstated.
http://www.monolithic.com/thedome/safe_home/index.html
Somebody was touting something similar at a "green fair" a few weeks ago--cute little prefab concrete/ferrocement/or something dome sections.
A Florida company that makes cute little foam domes also believes that that little building is pretty hurricane- if not tornado-proof--they don't guarantee them the way they do their houses, but one survived Andrew just fine.
http://www.aidomes.com/utilitydome.htm