-
Yeah, I've got f.lux on my laptop and Cyanogenmod on my phone with LiveDisplay (similar idea).
It'd be nice to have the option of not having a white background for LFGSS though, even though f.lux and livedisplay do temper it a bit.
TurtleRecall-
I tested a dark mode quite a few times, it looks terrible.
It looks bad because all images, avatars and other media assume that the background is white. When the background is black (or dark), transparencies are obvious, edges in .gifs are obvious, videos look too dark, and it all gets unusable really quickly.
I would like a dark theme, but I've never made one work with the content so I have never shipped one. I removed support for it after the pointlessness was too obvious to me. I could create another, but I don't feel web content has moved on enough to make it work yet.
Velocio
Assuming you're using a laptop, have you tried flux?
http://www.ampercent.com/adjust-screen-brightness-temperature-automatically-flux/8862/