Can you elaborate on how vignetting would be appropriate for a CRT filter
because a lot of CRTs would do that as they got older?
One of the limitations of the present design, though, is that the simulated beam has height but no width, so the resulting blurring is only vertical.
I dunno how much power glsl gives you, but could you hack it by, like, grabbing the entire frame post-render and applying a selective blur to it?
EDIT: actually that would probably destroy the scanline effect wouldn't it....