never heard of a pixel flasher, doesn't mean there isn't one, if there was I would suspect that it would come with each TFT!!
If a pixel is dead, then it's dead, as far as I am aware there is nothing you can do about it. Apparently there is a white paper on TFT screens detailing the number of pixels not working which would warrant an exchange. 4 springs to mind, when I first got mine I had 3 dead pixels and 1 smack bang in the middle of the screen that was red although the number was within the so called white paper rules the manufacturer agreed to exchange it as it was so off putting you couldn't help but get drawn to this one red pixel, a bit like looking at car headlights.
I believe legally there is little you can do, the only thing I would recommend is that if buying from a shop ask if they can power it up before you take it away, hard if it's mail order (as mine was), if they'll let you.
As the shop has suggested gettin this pixel flasher I would ask them where to get one.