Interesting. You could use a render view in another scene. So you would create a second scene with a full screen quad and apply a renderview material - the camera view from the first scene.
You could tweak the renderview settings to see if you can get the desired effect - like setting the resolution really low, maybe? I don't know. There are effects you can apply to objects, but in my experience they don't really work the way you expect them to, and are REALLY expensive in rendering time. I wanted to blur my reflections in my scene, and went out of real time, even on a simple scene.
I'm going to try this, though, it's an interesting problem to try to tackle.
EDIT: so I went ahead and tried this. If you set the Render View layer resolution to something really low - like 320x180, or 280x270, you get a pretty crappy view of the scene (the desired effect). I tried using Gaussian blur, set only to 3 radius, but it does use a LOT of rendering time to do it, so you may get the results you want from just using a really low resolution Render View without an effect applied.
#XPression