Alright, apparently what Wallboy says is TRUE. Sooner than T60p, I got this T43 15" (1440x1050 FlexView/IPS ?) with ATI Mobility X300 and have been testing it under older linux distro (opensuse 11.2) using free radeon driver. No eyestrain. For the first time in my life there was NO eyestrain under linux + LCD display. I'm pretty sure it's nothing to do with thinkpad display IPS or not. I was also thinking of trying out proprietary driver too, but I don't really want to break this system as 'fglrx' is known to cause more issues than any free linux driver ever did. With Ndivia is the other way around, though.
So, now that we are really getting somewhere, perhaps, a few more people should join the experiment and play with their old hardware.