> You're unlikely to find a PDF filter, however. I've surveyed most
> of the open source world looking for a decent one. There are a
> few, but they don't work very well.

Well, I have found this stuff to work well enough for my puposes:
http://www.foolabs.com/xpdf/download.html
http://www.glyphandcog.com/Xpdf.html
(look at e.g. the pdftotext tool) Perhaps you excluded GPL'ed stuff
from your search?