I like the idea - I actually had my screen colours inverted completely for some days. However...
Looking at one white on black site for a while and then back at the usual black on white causes some uncomfortable afterimages for me, and while I like spending some time here I usually have Matlab/Mathematica/etc. on my screen and don't like to be distracted by funny colourful spots (that's also why I stopped using inverted colours, it didn't work on remote sessions). Maybe that's just me though...
This could also interfere with accessibility issues, I'm afraid. But I like the style if you just invert the colours, giving it an also nostalgic pencil-calculations look:
Amplifying the background a bit wouldn't hurt, too IMHO.
I also like the sketchy style and colour choice of e.g. Crayon Physics
Screenshot http://www.kloonigames.com/crayon/screenshots/crayon_shot_02.jpg
but that's probably giving the wrong idea to someone with "advanced" questions. OTOH I can't help but smirk at the thought of a quite sophisticated discussion written down in wax colours :-7