Has this ever been attempted? I don’t quite like how the 2x variant looks, but the 3x one looks alright, and perhaps at higher scales it could look quite decent.
RGB2x
RGB3x
I don’t know if it’s related, but there is this shader: http://www.mediafire.com/download/58tow7m2nqd6cpy/caligari_scalines_-_rgb_triad.shader
It kind of resembles it at least.