None of the screens we've covered this year (16 including reviews not published yet) have a backlight control.
This is strange, according to this source:
http://www.tftcentral.co.uk/reviews/dell_p2414h.htm , the brightness control actually controls backlight luminance(at least for the reviewed display), so reducing it you can get lower black levels and at the same time maintain similar contrast (dynamic range). Also this is not unique to the display covered in the review, a lot of other displays reviewed by them behave similarly. Admittedly it didn't have separate black level control which would leave luminance untouched. However I think this is being controlled during calibration by software LUT.