My PSP has a few dead pixels, but I care more about dust. When I put my custom faceplate on, dust kept clinging to the screen itself and the screen cover on the faceplate. No matter how hard I tryed cleaning it and taking it back off, more dust would get on, so I've just learnt to live with it.
Also - Dust/dead pixels are harder to see when the PSP is on a lower brightness setting, so that could help a little.[addsig]