After I posted, I did some searching, and it appears like something could be made using SOLR or Elasticsearch. Both seem to have methods/plugins for filesystem

After I posted, I did some searching, and it appears like something could be made using SOLR or Elasticsearch. Both seem to have methods/plugins for filesystem indexing and document importing/analysis, as well as easy interfaces to allow for any language to be used for development. Combining all of that, plus some dev work and such a search appliance looks doable for a home system, using only a single node. For the hardware, I figure I could potentially use some old stuff I have (thinking like a Core2 Quad with 16gb RAM and a large hard drive would be fine). I could probably stuff it into an old half-depth 1u server case. The problem now is finding the time to build it...