It is possible. However all the methods I have tried are very slow. You can read just the text using Active X portion of Acrobat reader that is installed when you install reader. From there you can customize the search anyway you like.
My best advice to you is to build a database that you can search first for your results to narrow down the file access time. On my system I have roughly 13,000 PDF files. In a directory with 100 PDF's it seems to take about 4 minutes to search the text and pull up the results. Most of my users won't wait that long.
If you are going to start tearing apart the PDF files like this you might think about biting the bullet and ordering Adobe's SDK package. Last I knew it was about $1500. I do not have the package here, but at my last postion I did and it had a search built into it as a function. That seemed to be very effiecient.
Sorry I couldn't be more help.
Cassidy