Action cams and phones with manual controls and SLR lenses?

I think that it would be very interesting to have a camera such as the Gopro, or maybe even a cameraphone and be able to mount SLR lenses to it! Just think about it, manual control of focus and/or aperture, along with big touchscreen monitor! (BackBone is one example). If the Gopro or other action cams gain full manual control, then I'm definitely considering buying such a combination over an A7 series from Sony. The thing is, I think that I'd prefer that the camera be heavier than the lens, not the other way around, therefore giving me better stabilization. I don't know about you, but this definitely seems a fascinating concept. Phones have a great user interface, even better than that of many, of not all, cameras. I think that the user experience would be very intriguing!