I just went and ordered a black-on-green display. In normal, indoor lighting, the display is readable with no backlight at all, in fact, you can't even tell any difference if you turn the backlight on full or not. In darker lighting conditions, the backlight makes a difference as would be expected.
If you get in your DeLorean and go back a few decades you will find out that this is a non-issue since that's all that is available. You wouldn't want to mess with the backlight, most required 150 (One-Hundred and Fifty - not a typo) volts.
Maybe you can ask where liudr got his lcd ...
I believe he gets many of his parts from a surplus house near Niagara Falls*. In that case (or from any surplus house) they might not be completely consistent from one month to the next.
Don
- [Edit]: Here --> http://www.dipmicro.com