I used Make, inotifytools, pdflatex (or similar), "xpdf -remote", and $EDITOR to get an almost-instantly-updated view of papers and my thesis, including all figures and illustrations.

When any of the dependencies of the final output changed, inotifywait noticed and kicked off a "make", and then notified the xpdf instance to refresh itself. xpdf was nice enough to try to stay on the same page when it did this.