So, "in 2003, Oxford University Press acquired the project from Random House and immediately began the work necessary to complete the dictionary. Oxford"s release of volume III and volume IV will be forthcoming." Not to be impatient, but it's been 9 years. Have you sent out any inquiries to Oxford U Press? It'd be nice to see this series go beyond "O" not to mention completing the series on my shelf.
But in the meantime, I do appreciate the sharing!