http://www.ps3trophies.org/forum/ann...tml#post574954

UPDATE 3 (8:10 EST) I CAN CONFIRM THAT THIS ISN'T A PSN ISSUE ANYMORE, IT SEEMS TO BE A FIRMWARE ISSUE. MY PS3 HASN'T HAD INTERNET CONNECTIVITY SINCE JULY, AND I JUST TURNED IT ON TO SEE WHAT WILL HAPPEN, AND THE DATE IS 12/31/1999. I HAVE A 40GB ORIGINAL PS3. I CHECKED MY TROPHY PROGRESS AND IT'S STILL INTACT BUT I DID NOT LAUNCH SSHD, SINCE I DON'T FEEL LIKE RE-DOING ALL MY TROPHIES
Looks like our original find is correct, PS3 Slims (120/250 GB models) are unaffected. Those people can log into PSN without the fear of this happening to them as of right now.
In other words, if you were an idiot and got the Slim version, you're fine. If you had the intelligence to buy a larger model PS3 (like me), you're hosed.