How to search PDFs and extract matching pages with Automator?
I realise this is a year after you asked the question but I liked the challenge. So, in summary this is how I would accomplish this...


For every PDF in folder, convert it to Text.
Use a perl command to search the text files for keyword and return the page number(s).
Use command line tool to extract page(s) from PDF.
Merge extracted pages.


You can do the first part easily enough with applescript/automator. 

The perl command to get the page numbers is:

perl -ne 'print "$1$2" if /blah/ .. /--- Page (\d+) ---(\n)/' 

The command tool to use to extract pages from PDF file can be found at
users.skynet.be/tools/ 

Finally to merge the single pages can be done with automator or the above tools as well.

Hope this helps.