Logically separated layers. Not "you don't like the display server... well you have to re-implement everything from scratch yourself". You know, normal computer things.
edit I'm thinking basically of this use-case, but with the projector in the phone.
http://www.brookstone.com/laser-projection-virtual-keyboard
edit apparently this is as close as is available (almost)
http://www.ctxtechnologies.com/products/vk300-iphone-docking...
Bluetooth keyboard and mouse, of course, already on the desk. Chromecast hooked up to the monitor. Use one of the Android automation apps to automatically mirror the display via Chromecast when the phone is in range of the BT keyboard / mouse on your desk and when it is laying flat on a surface (plopped onto the desk).
Not perfect. Chromecast latency might be an issue. You would still have to plug it into a charger if you don't have wireless charging. But it should work.