Sony's minsucule QX Lens Camera offers the specs of its high-end RX100 point-and-shoot--a 1" sensor and Zeiss F1.8 glass--but clips right onto a smartphone. It hooks up with an iOS or Android app, via WiFi or NFC, thereby letting you use the phone as the camera's viewscreen. (There's an even smaller version, too, though its sensor and lens aren't as good; you may as well just get a Nokia 1020.)
I rather like the idea of a tiny, high-end camera that can just clip-on to anything--cellphone, webcam, helmet, bike, etc. But the RX100 is already small enough, has more features, and is only a little more expensive. At $500 for the version worth buying, that QX is a pretty penny.