Gnowsis is a project lead by Leo Sauermann. I've read about it before but apparently never blogged it. Many of the ideas like the Semantic Desktop are worth noting. This type of application is something that seems to be coming up again and again.
He gave a list of features to add: optional triples, update language, protocol on the web and a protocol on the desktop (ODBC like). The first two are handled by iTQL although the second is more elegant than first. Kowari/TKS has always had a driver. The Kowari Lite client, currently the executable iTQL jar, is only about 1MB and doesn't include things like Jena.
why I love Patrick Sticklers URIQA approach "Building RDF aggregators is not an easy task. I have tried it in many different ways, and had varying forms of success. If you want an easy approach that does it, think about concise bounded descriptions."
I do think that the resolver idea, using the FROM clause, views and defining caching and updates, is going to be an easy way to do RDF aggregation.