Im not sure about other countries but in the UK the official line is a single dead pixel in the middle box is sufficient to permit an exchange. In the surrounding boxes a total of one dead pixel is acceptable in any one box. However, two dead pixels side by side ANYWHERE on the projected image would be accepted for replacement..
Over the last year Ive only come accross these two posts on our UK avforums.com who complained about dead pixels on their 11HT. They both bought from the internet so the ecommerce retailer would of been relying heavily on the response of Sony UK I presume http://www.avforums.com/forums/showt...threadid=49331 and http://www.avforums.com/forums/showt...threadid=37788 . They seemed to get a replacement just with 1 dead pixel. Its always a good idea to check with your dealer though imho as every projector manufacturer seems to have a different dead pixel policy in different countries.