From what I understand iPhones support external displays out of thebox, so you could use one as your main computer and do any productive stuff like development,

From what I understand iPhones support external displays out of thebox, so you could use one as your main computer and do any productive stuff like development, video/3d/photos editing, anything really you can do on a computer with the liberty to install open source tools, develop/open drivers for anything connected to usb or bt, etc.