the closest you can get to that in vanilla is to find the largest cluster of boulders ever and dig underneath. this is a bit tricky and sometimes not possible if the land wont let you dig deep enough. BUT... if you can find a huge boulder in the side of a hill then you got a shot. I went out a few times specifically looking for a place to do this and so far no luck. got close once but the space was just too small AND there was a troll spawn close by enough to be problematic.
Iv'e been in silver pits in the mountains that went into boulders that can be made into small camp sites but never big enough to do what you're talking about.
In the future i'd like to see them add the ability to raise terrain over stone walls and floors. that would make it possible to truly build and live underground