h20....It may be hard to believe, but I have also encountered recessed "bell" boxes. The most recent was installed in a bathroom, where the light switch usually is.
What's hard to believe is the amount of work necessary to do this...then cover it with a standard faceplate!

Funny thing about this trade....the longer you're in it, the more crazy stuff you see! Heck, I've heaped so much sarcasm on various DIY'ers and hack 'handymen' that I don't have any left over for my friends at ECN! :-)