- Sony briefly had a 'screenless' series of 'smart lens' cameras around 2014 - the Sony QX1 ( https://en.wikipedia.org/wiki/Sony_ILCE-QX1 ), QX10, QX30 and QX100 ( https://en.wikipedia.org/wiki/DSC-QX100 ) where you brought your smartphone to act as the screen. I think the concept at the time was just too abstract and clunky since it meant clamping on the camera to a phone, and probably had latency issues. They've also tried to make some high-end smartphones with better camera apps but it was a niche audience.

- RED also had some smartphones with a connector interface to supposedly add cameras, but the product line flopped pretty quickly.