In a moment of insanity (but a great learning experience), I gave myself the challenge of writing an OLE DB provider for SPARQL. It is built on top of the SemWeb libary which has saved a substantial amount of effort and also brings some powerful functionality to the table very quickly (Thanks, Joshua!)
The provider as constructed implements a readonly OLE provider that supports all four SPARQL query types and interfaces to SemWeb through COM-Callable Wrapper. It is not extensively tested yet but seems to work with most of the queries I have now put through it, and of course being built on SemWeb it is able to read both local and remote SPARQL sources.
Moral of the story: populate Excel tables with SPARQL queries.