In short, most notebook displays are rubbish as they use very low quality TN panels and their backlight only covers the standard for notebooks but otherwise poor 45% NTSC. There are very few notebooks that use better TN panels, improved backlighting and actually can be used for photo editing, so I will just list the best options.
13.1"
Sony Z, White LED backlight, 100% NTSC, semi-glossy
http://www.notebookjournal.de/tests/...gn-z11vn-638/3
15.4"
Dell Precision M4400, WUXGA RGBLED backlight option, 100% aRGB, glossy
16.4"
Dell
Studio XPS 16, RGBLED backlight option, 100% aRGB, glossy
http://www.notebookcheck.net/Review-...k.14431.0.html
http://www.notebookjournal.de/tests/...o-xps-16-790/7
Sony
FW, "XBRITE-FullHD" dual lamp backlight options, 100% NTSC, glossy
http://www.notebookjournal.de/tests/...n-fw11zu-619/3
17"
Dell Precision M6400, WUXGA RGBLED backlight option, 100% aRGB, both glossy and matte
HP Elitebook 8730w, WUXGA RGBLED backlight option, 100% aRGB, matte
(Both ar supposed to use the same screen, which is also advertised as 8-bit unlike almost anything else on the market.)
For the record, the ThinkPad W700 and the 17" MBP displays cover 72% of aRGB and NTSC respectively.
18.4"
Sony AW, glossy option - 108% NTSC, matte RGBLED backlight option - 137% NTSC
http://www.notebookjournal.de/tests/...n-aw21vy-843/5
Now I would advice you to base you decision mainly on the screen quality rather than secondary factors as you don't have many options anyway. I posted the available reviews from Notebookcheck and Notebookjournal (
use Google to translate if needed), which are the two sites that provide objective information about display quality since people's opinions are subjective and useless.
Also, as you may know business-class notebooks are more durable/reliable as they are designed to last and can handle more abuse than consumer ones, so if the glossy screen isn't an issue, I would suggest the Dell Precision M4400 as it's seem to meet your requirements about durability, battery life and screen quality.