Not sure if everyone has seen John's latest post about indexing org files
with swish-e:

http://kitchingroup.cheme.cmu.edu/blog/2015/07/06/Indexing-headlines-in-org-files-with-swish-e-with-laser-sharp-results/

It's very impressive.  It strikes me as a step towards an incredibly
ambitious project that would bring file indexing inside of Emacs -- so it
would not longer be necessary to go out to a shell or a Desktop Search tool
in order to find files that contain particular search terms.  I'm looking
forward to your next steps, John!

Matt