Something to add to the discussion.
http://www.sciencedaily.com/releases/2005/04/050418204410.htm
(sorry I am so late getting to the thread) sigh.
... whose light has been stretched out or redshifted to nearly double its original wavelength by the expansion of the universe ...
I'm picturing sort of filmy rubber bands here ...
If I'm reading that right, Webb and Davies measured the dark line ("missing") wavelengths that were absorbed between there and here instead of the bright line emissions from the source.
If so, that's a pretty questionable methodology.