updated paper Dec 2009 from Hawkins with a larger sample set
http://adsabs.harvard.edu/abs/2009ASPC..413...24H.. seems Hawkins is moving towards the micro lensing solution...
"The main result of this paper is that timescale measures of a large sample of quasar light curves do not show the effects of time dilation."
"The lenses are most plausibly primordial black holes"
"This implies a population of compact lensing bodies sufficient to account for the dark matter"
Looking at the list of abstracts from other papers, from the
same publication it seems those other alternatives are still being explored by many.
Also... Thanks Steven,
So in short?
Gravitational Redshift = The frame is accelerated
Cosmological Redshift = The frame is expanded