At BibleTech I learned of an initiative to create a Bible reference microformat. At the conference we mused about a tool that would be able to spider these microformats and then return a set of matching results. So if I searched for Matthew 1:1, I would get back results where a bibleref metadata tag had been embedded on that page for that particular verse.
Well it appears Yahoo is working on a meta data search engine. I read about it on sitepoint.com and even found a link to the research version. Perhaps an engine like this could be told only to search for bibleref meta data. Tapping into a main search engine data store, like Yahoo's, is probably the only surefire way to return comprehensive results.