Hi,
it would be great to have such a plugin for dokuwiki.
I think it could be done with some pdf2text tools in combination with a search engine like Lucene (see:
http://www.jguru.com/faq/view.jsp?EID=862443).
With Typo3 we use mnogosearch (
http://typo3.org/extensions/repository/view/mnogosearch/current/) which is also able to index pdf, excel and word documents.
A problem could be that those engines needs a database which is not needed for a standalone dokuwiki.
If anyone has an idea howto index media with doku wiki, I would really appreciate it.
Greetings from Austria
Andreas