Yeah I have this bowing on My Aussie version of the XBR910. Unless I am mistaken, as it has been sometime since I read his comments, kenTech suggested that the horizontal bowing required magnets applied to the corners of the CRT.
Others in other forums have suggested there is a service mode fix for this.
I'll have to read my service manual this weekend and experiment and see if there is a non-magnet fix.
It didnt bother me because after 2 years of looking for a landing fix I was over the moon. Besides LCD, plasma, at least the ones from 2 years ago, made me cringe.
i never noticed the bowing when I first got the set. maybe it was always there and I just didn't notice it