In college, I built my McIntosh C-20 into a water-bed frame. I made one side large enough to serve as a seat, covered it with carpet, and made the top hinged to open for access to the pre-amp and tuner (Sherwood). My amp was a naked Crown D150 so it went under the bed, and the speakers were JBL C37 030s so they weren't built-in! The turn-table (Thorens) was in the headboard/shelf.
The bed is long gone. All the hi-fi stuff is still here (except the Thorens) and working, and my first girlfriend to share that bed has been my wife for the past 28 years—and we still sleep on a waterbed. Some things never change!