In reply to Joel Perkin:
As far as I know, smallest (usable) camera with changeable lenses is Panasonic GM5 (but wait for the GM7 that is promised for the spring). With a 14 or 17mm pancake it's rather small (35mm FOV would be 28 or 34mm).
For a non changeable lens camera, Panasonic LX100 and Sony RX IV are most likely the options to look for. Not much more compact than the GM5(or hopefully the GM7), main difference is naturally no protruding lens.