Keeping a laptop backlight off

[Aidan Gauland <aidalgol@no8wireless.co.nz>]

I just installed a Pixel Qi screen in my Acer Aspire One am already
enjoying the increased readability in sunlight, but there is a small
problem I need to address: when I turn the screen backlight off via the
Fn key (Fn+F6), the screen goes into minimal-power, monochrome mode;
only problem is the screen comes back on as soon as I move the mouse or
press a key, which makes it impossible to use the laptop with the screen
in this mode.  Is there some /proc hack to *keep* the backlight off?

--Aidan