That year's Sony sets (V2500, XBR 2/3) had clouding issues. I'm not entirely sure why Sony is still selling the V2500 since it's been out about a year and a half, if not longer, which is ancient in LCD time. The V3000 and XBR 4/5 had less clouding issues, but still present in some settings that I have seen. It's just how LCD is. The only panels I have not seen a lot of it on are the gloss screen Samsungs (66/65, 71, A650 models).
Like you said, clouding is not something one can really see in a showroom setting, when plasma can sometimes look a little darker and not stand out as much.