Have you looked at any of the research to come out of http://start.csail.mit.edu/index.php?
I've also been working with Quepy a bit lately. Very cool stuff. Are you able to comment at all on what you're working on, or is it "super secret stealth mode" stuff?
For us, we already do semantic concept extraction using Apache Stanbol, against content that flows into our enterprise social network product, and then store the associated triples in an RDF triplestore. We have a primitive search feature exposed, which lets you query using SPARQL, but realistically, we know "normals" will never, ever, ever, ever write SPARQL queries, so the big push is to do automated translation from natural language (even if it's a slightly restricted natural language) into SPARQL so users don't have to think about triples and what-not.
If you're not in super-secret stealth mode and ever want to compare notes to talk about this stuff offline, feel free to shoot me an email.
