Jerry Angiulo had a great one across the street from his Prince Street headquarters/office. It's described near the end of the book Underboss.
It was in a three story walk up, but on the second story only 1 door was visible. The other door on that floor had been bricked over and the apartment that had lied behind it was only accessible from another apartment within the building.
Yeah. That's almost the same as living like a mole under the ground.
