There's a number of silo conversions that have been done in the past, some with fantastic results: http://www.silohome.com/ http://dornob.com/ultimate-underground-home-converted-nuclea... http://www.gizmag.com/luxury-survival-condos/34861/ Can't help but think that maintenance of such a thing could be very challenging after a while.
A little reminiscent of the Fallout post-apocalyptic game series.