no chance for a replacement. two isn't that many, if you ask me...
my PB 12" screen was perfect when i got it. after 9 months, it developed one dead pixel. so even if it's perfect now, it may fail later. and there's no guarantee whatever the replacement you fight for will have a perfect screen.
massage and see if it helps. i hope it does.
it may sound ridiculous, but if LCD manufacturers had to guarantee no dead pixels on all LCDs, their prices would be nowhere close to "affordable."