I just got my MBA 2nd gen (1.6Ghz, HD), manufactured week 50, and can confirm that the problem still persists.
I too think that all MBAs have this issue, and the defect just isn't visible to everyone (just like running a CRT in 60hz was fine for some people). Also, the lines are mostly visible when looking at something which is bright and mostly in one color (different shades of light gray and red seem to be most prone to this). I see them constantly when browsing the web and am able to reproduce it 100% with the test image on
http://tft.vanity.dk/monitorTest_scale.html, and the flickering with
http://www.keithstravels.com/travelog/photos/desktopsplit-loginscreen.jpg. Also, being in a dark room will help.
On first startup I instantly saw that something was funky with the screen but it took some time before my eyes started focusing on the lines, and once you have spotted them you will see them constantly.
My eyes get really strained by reading text as the lines 'behind' the text in the bright background causes what could be best described as a 'hologram' effect, ie you get a strange 3d effect which makes it VERY hard for your eyes to stay focused on the text.
I will either take this unit back (as it also suffers from some major backlight bleeding in the top of the screen), or ask for a screen replacement later on. This is my first Mac so can they guarantee a screen replacement via phone, or should I just go for a refund?
Also, this is DEFINITELY a hardware problem; no firmware update could ever fix this.
It looks like there's air bubbles/patches of air between the LCD film and the glossy screen 'glass', or rather between the LCD panel and the backlight. How could a firmware cure that?
Tommi