I don't know about wireless monitors, but Asus (and probably other manufacturers as well) make this tiny PC with built in WiFi that comes with a bracket that allows you to mount it on the back of most modern monitors. ASUS Eee Box - Simplicity
With this kind of set up, all you would have to do is physically mount the monitor (with piggy-backed PC) to the ceiling and run power. For the power you might be able to splice in a wall outlet into the existing power line for the light or ceiling fan. Why would you want to watch it while lying in bed anyways? Oh, never mind, I figured it out...