This frankenstein came together mostly due to the deals I got on the various parts. Then I decided to have this rig be my entertainment center, or whatever you call it.
Screen is projected by a 1080p native 3200 lumen projector, not the best but it looks decent even with ambient light. I highly recommend a gray screen as opposed to a white one for better contrast between light and dark. This only helps if your projector is bright enough however.
All in all this works great. The lapboard is very comfortable and I don't notice any lag. I've been playing Borderlands 3 on this 120" screen, my couch is about 13 feet away and it looks great. Not incredible mind you, but the best bang for the buck as far as size and picture. FYI it gets ~40-50 FPS on Ultra high settings on Borderlands, but with this projector screen setup there's no point in doing that so I leave it on the next best setting, extreme I think it is, and get 60-70 fps. Not bad.
I also have an Nvidia shield as part of my setup to use as a 'receiver' if you want to call it that. A must if you want have an easy time of it. I can navigate my desktop or dozens of apps like Netflix or Plex with a game controller. You could just use your desktop with a mouse, but navigating with the controller is really convenient. I highly recommend it.
Note about the pics, I will be hiding all the power cables and ups in/behind the bookcase, and I will also be putting the tower on a level surface of some kind to allow the power supply to vent properly.