The best part of the latest release of JRDF is not code that we've written but Restlet. Restlet provided an excellent abstraction for providing RESTful web services and allows deployment without a container (the distributed and local server are both about ~6MB in size).
This has allowed us to quickly develop a web service that answers SPARQL queries that can be from one or many machines. We're using it to query the results from MapReduce tasks in our Hadoop cluster but it could probably be used as a general way to query other SPARQL services.
It's still early days and there's a lot that still needs to be added (and re-added) such as limiting result sizes, being able to choose which format to return and better JSON support. A lot of it has been pushed out in time to show a front-end at SSWS.
Download it here.