I'm a huge fan of LogicBlox and RelationalAI, and the research done at both had a huge impact on me as an undergrad!
While you're here, could you provide some insight on why you folks went with arbitrary width tuples for your datamodel? Limiting youself to triples seems to drastically ease the implementation of WCOJ algorithms without much loss of expressivity, and provides compatibility with existing RDF research.
E.g. in our system we materialize the 3!(6) indices required, which allows us to pick variable/intersection orderings on the fly without a planner.