A little birdy has just told me that Charles Forgy has finished his latest creation, Rete NT. Where the NT is for "Next Technology". The engine has been built for parallisation and concurrency in execution and promises to be atleast 10x faster than his previous Rete 2 for large systems.
I know that Charles has been researching parallisation and concurrency for rule engines for over 20 years and when we last spoke he was talking about set oriented theory. So I'm guessing it has something in the lines of "Collection Oriented Match" and "Set-Oriented Constructs". Anyway can't wait for the official release to get more details, I suspect it'll be announced at his PST site soon: Production Systems Technology.