If you didn't mind rasterizing* the PDF, you could use
imagemagick. See the two attached PDFs. I created output.pdf from input.pdf with the single command:
Code:
convert -density 300 input.pdf -negate output.pdf
(If that means nothing to you, let me know and I'll try to give full or at least fuller instructions.)
*Rasterizing the PDF means converting each page to an image inside the PDF. On a fixed-resolution device, it should look exactly the same. However, since the text has been replaced with a series of images, dictionary and search functions will no longer work. The PDF is usually much larger in file size too.
If you need a solution that preserves text as text, I'll have to think about it some more, though it's probably possible with the right software.
However, I think with an e-Ink device such as a Kindle, Nook or Sony Reader, this would drain the battery
a lot faster. (On the flipside, with an LCD device such as an iPad, it might even improve batter life.)