There has been and probably still are a few underground bunkers/missile silos that had been for sale in the US recently complete with kitchen, living quarters, working water/electricity and even their own emergency power plants. Shockingly they didnt cost all that much, i've seen small 2 bedroom houses in NJ go for more.
So if you're looking to start your own army just hop online and find a bunker/silo for sale, its not that hard.
here's some info on bunkers/nuclear silos for sale in various countries near you!
http://slashdot.org/article.pl?sid=02/09/11/230203
http://www.theinquirer.net/?article=16631
http://news.bbc.co.uk/1/hi/england/2164659.stm
http://www.itvregions.com/Granada/Ne...r+for+sale.htm
http://www.cronaca.com/archives/001150.html