Not really the approach you describe but quite some time ago I came across an experimental project which used a C implementation of Apache Lucene (I think that

Not really the approach you describe but quite some time ago I came across an experimental project which used a C implementation of Apache Lucene (I think that was called Lucy) to implement a new approach to file management, based on full-text search, where you don't store the files in a hierarchy but use more a concept liket tags and what a file is about and stuff like that. I thought it was pretty cool and the demo I tried worked pretty well for me. Unfortunately I can't find it anymore and can't remember the name or anything. I think this is a very interesting approach.