I have neither received an email or call from Apple announcing a repair program, nor I was aware of it. Don't you think they had the obligation to acknowledge customers about this issue, and by not doing so they acted in bad faith?
In my case, I purchased the $349 apple care but never had to use it. I purchased the laptop on January 2nd, 2008. Unfortunately, the black screen happened few months (April 2012) after the 4 year repair program ended. Some or many people didn't purchase the apple care but were "fortunate enough" to experience the issue during that interval. Why Apple is discriminating against customers?
I'm not going to blindly defend Apple in this situation, but I think they did as much as they reasonably could. Many machines were fine, and this may have caused excess panic if this was sent out as a notice. I do know the lawyers sent out a thing for the actual NVIDIA settlement that affected these machines and those from Dell and HP, although I don't remember if it took away your eligibility for the Apple program (I doubt it).
Although many people keep their Macs for more than 4 years (myself included), I think that was a reasonable amount of time, and the fact that Apple would reimburse you for repairs made related to this if you were previously charged. I don't think Apple was discriminating necessarily, as offering different coverage for those who bought AppleCare could lead to a slippery slope for other repair extension programs. As someone who bought AppleCare myself, I can see how you feel it was unfair that those who didn't buy it were still covered (at least in that area) as long as you were, but I think this was a good faith measure to back a product that they sold for all customers. Now, if they had repaired other components (hard drives, batteries, etc.) for those who didn't buy AppleCare, I could see how you'd be steamed.
I seem to recall a similar program back in the early 2000s for the iBook G3s - I worked at a school where we had them and it was a similar graphics chip defect - in that case, the extension was three years for issues relating to the graphics chip, and for repeat offenders, the company simply exchanged for an iBook G4 (I know many individual users who had this happen, too) - in that case, Apple supposedly contacted some customers, but I have no experience as to if this actually happened or not: http://reviews.cnet.com/8301-13727_7-10343732-263.html#!