Here's a summary of my experience, for reference. I've tried to include all the details in one place, as finding a full account of any particular user's experience in this thread can be pretty tough sometimes:
12/2006 Purchased KDS-60A2000 from Amazon for 2.2k.
5/2010 Green/yellow staining begins to be noticeable
5/31/2010 Contacted Sarah Kepler on Facebook
6/1/2010 Sarah responds saying optical block replacement is required first step. I fume, knowing it will also be defective, as Sony has known since the time of manufacture. I don't pursue, as it sounds like a hassle to arrange service visit for a certain repeat failure.
11/30/2010 Bought 58" Panasonic S2 plasma to replace 60" SXRD, vowing never to buy Sony again. (My 50" GWIII also had optical block failure.)
late-12/2010 Realized from this thread that Sony was now replacing SXRDs without requirement of futile optical block replacement.
1/02/2011 Emailed Sonylistens@am.sony.com
1/03/2011 Received return email from Sony (Sarah Kepler) with Event ID and 888 number
1/03/2011 Called Sony 888 number and selected free 46EX710 vs. $325 60EX500.
1/04/2011 Email from Sony acknowledging my selection of free 46EX710.
1/06/2011 Mailed pic of yellow-stained TV picture.
1/12/2011 Email from Sony acknowledging picture of defective set was received.
1/20/2011 Email from Sony with DB Schenker tracking number and 1/25 est.
1/25/2011 KDF-46EX710 delivered.
I am a bit baffled by why the backlight illumination is so non-uniform on this set. I fully expected to get it and post that the people on this forum are just too picky and that the problem is overblown. Well, not really. If I paid full price for this set, I'd probably be disappointed. Any time there's a dark screen, you'll see it.
Still, for normal viewing, it's a great TV, and preferable to me over the Panasonic plasma in some ways. It's also in my bedroom, since I'd already replaced the 60" in the living room on my own, so I am not as critical. I'd not even consider sending it back.
Overall, I feel that Sony adequately addressed the lack of value in my SXRD by providing this set to me for free. Actually, given how quickly technology has changed and PQ has improved, I think they went above and beyond. As great as SXRD sets were five years ago, these new sets blow them away.
Thanks to everyone else who took the time to post here. It was very helpful.
P.S. Since I only have a Tivo in the living room and have avoided a cable box in the bedroom, the TV Guide guide in the EX710 is a great feature for me. The internet video features will go unused, though, as I have an Apple TV connected, which has a far superior Netflix app.