You could always go the billt Greenlee route.
http://www.downrange.tv/forum/index.php?topic=7060.0
I'm finding out that whatever "safe" you buy, it isn't big enough, and fills up too fast. That, and you start running out of places to put them. I'm in the same boat as kilopaparomeo. No basements here in Arizona. Going the cast concrete wall route you have to be sure of the footing that will support it. That means possibly drilling down to pour solid footings to build on. That gets real expensive, real fast. Plus, in a subdivision you might as well put up a sign in your front yard that says, "A lot of valuables will be kept here!" You'll be the talk of the town no matter if you like it or not.
That in itself causes break ins. Word of mouth is your biggest danger in owning guns. Not to mention the talk the permits would generate from local building inspectors at the local bars on Friday night. Never underestimate how much people talk about you, or what you have. All it takes is one wrong person to hear it. Nothing will generate more talk to the wrong people than a teenage daughter who brings a lot of boys over to your house. They see everything, and talk to everyone. Boys and guns generate way too much inquisitiveness. It not if, but when you'll get hit. I'm lucky in that regard, we have no children and entertain very little, if at all.
The biggest problem with gun collections is you acquire them over the span of many years. A bit like growing out of your pants. By the time you notice it, you have no more room. I think the best protection at this stage of the game is just to stay home! Besides it's cheaper!
Bill T.