Yeah, that was some kind of a bad joke dude, I didn't really meant it for you to implement!
I loved vignette shader, thank you for you time you've spent on it and for sharing it with us as well.

Plus, maybe as you've started with vignette (camera) effect, maybe you could go on, and create dynamic lenseflare effect? Which could be easily added to a camera chain effects via pp_add, so we could combine it with other postprocessing shaders, like hdr etc. That would be awesome I think, but I don't know, is that thing complex or not mate. Sorry if it is, that's the only idea I had in my head for now.