This has happened already, a few years ago the Sherlock Holmes estate authorised a new novel The House of Silk written by Anthony Horowitz. http://en.wikipedia.org/wiki/The_House_of_Silk
I'm really interested in the OOCSS approach, it's efficient, maintainable and modular, and although it's not perfectly semantic the trade-off is minimal. I first discovered it from the Velocity 2009 conference, and Nicole Sullivan's talk from Web Directions North - http://goo.gl/yLkby
Tokenization was a simple string split on whitespace, and no stemming. It was quite a large Mongo dataset, so only a fraction of the index and data would've been in memory, it could've easily been quicker for a smaller dataset living in memory. For me, one of the benefits of Lucene is the powerful built-in query parsing, tokenization, analyzers, etc.
This isn't really supposed to be a proper full-text index feature, instead it's building a rudimentary inverted index using a string array property. It's possible to create indexes over array properties in MongoDB, which is very cool, and increases performance to an extent. But even with an index, this approach to full-text was much slower for me than an equivalent search against the same data in Lucene.
I'd love to see a MongoDB component that replicates data from the oplog to a dedicated full-text store like Lucene or Solr.