I was wondering about this since a while.
It could be interesting, in low quality scale, to be able to say to a specific shader to render AFTER the upscale.
Perhaps with a little checkbox in the effects window. (a new column)
I'm asking this because when we work with low resolution games and want to add a shader like 'scanlines', 'bulb' or any deformation shaders, the result is often awful after the upscale.
I don't know if it's conceivable. Just asking.