It's an interesting idea but they won't be seeking approval for single-pilot operation: they need approval for zero pilot operations during cruise. When I leave the flight deck to take my morning dump, then it either needs to be left empty but locked (that'll be a laugh if the keypad fails) or with a member of cabin crew in it, which is laughable from a security perspective. Or you extend the flight deck backwards so that the bunks and toilet are enclosed but then you'll lose galley space, access from doors 1, and several rows of seats.
Or you could just have two pilots.