Wow, first let me start by saying how impressed I am with this thread!! I have never seen this type of comradery to try to determine if there is a problem, and if so, where is the problem. I am very impressed by Miniz knowledge and drive to try to educate others who have this problem, or those who may not even know they have an issue.
I am the repair tech that was at Miniz home today. I promise to use this forum to update everyone on my findings regarding this issue. I do not own this model, but I did stop by a local Best Buy to see if they have this set and how it looks. They had both the 46XBR2 and XBR3. It was hard to see if the XBR2 has this symptom since it is under the scorching lights of the main sales floor, but the XBR3 is in the 'special' Magnolia department. The symptom was very easy to see as soon as the video content changed from a widescreen image, to a full screen one. On all four corners, obvious bright spots. I briefly mentioned this to the 2 salesmen, one didn't even see what I was talking about (proving that not all HT sales staff are competent), the other did see it, but tried to downplay it since there were customer's within ear shot. They wouldn't admit if they had any exchanges or complaints on either of these two models.
If anyone has any questions, I will try to check this forum on a fairly regular basis.
By the way, Miniz... that is one sweet Mini you got. I have never seen an authentic Mini in that condition.